The Bluesky AT Protocol is designed as a federated social web protocol that emphasizes decentralization and user control over data. It facilitates a network where users can create and share data, which can be accessed and interacted with by various applications across the platform. The underlying architecture promotes the idea of "speech vs reach," encouraging a balance between expression and the dissemination of content.

At its core, the AT Protocol integrates concepts from existing social web protocols like ActivityPub, while also introducing its unique features aimed at enhancing security and collaboration across platforms. The protocol is currently in a state of active development, with ongoing efforts to align with relevant standards and best practices, including potential submissions to independent standards bodies.

Introduction to the Bluesky AT Protocol: Core Components

The Bluesky AT (Authenticated Transfer) Protocol is an open and decentralized protocol developed to power the Bluesky social media platform.

The key principles of the AT Protocol are:

1. Full user ownership and control over data
2. Data integrity via secured and authenticated data transfer

The AT Protocol enables a federated network architecture, where multiple independent servers work together to form a single interconnected social network. This makes the platform decentralized and not dependent on a single central server.

Key features of the AT Protocol include:
1. Identity management through decentralized identifiers (DIDs) that allow users to self-verify their accounts.
2. Data portability, where users can move their social media data (posts, likes, followers) to other platforms.
3. User-controlled moderation and content labeling services.
4. Custom algorithmic feeds that users can choose or create themselves.

How does AT protocol impact social media experience?

The AT Protocol addresses the issue of social media feed algorithms by providing a framework for creating and sharing custom feed algorithms called "Lexicons". This allows users to select the feed algorithm they want to use or even create their own custom algorithm by combining different Lexicons. The protocol separates identity, data storage, and service provision, giving users more control over their social media experience.

Overall, the Bluesky AT Protocol is an open, decentralized framework that aims to give users more control over their data and online identity, while enabling interoperability between different social media platforms.

Comparison with ActivityPub

The AT Protocol, developed for Bluesky, presents several distinctions when compared to existing protocols, notably ActivityPub, which is a prominent standard for decentralized social media.

Decentralization Approach

While ActivityPub decentralizes content across various servers, enabling users to post and interact across the "Fediverse," the AT Protocol approaches decentralization at the individual user level. This means that users maintain a singular identity across the network, which is customizable. If a user decides to migrate from one server to another, they can take all their data—including followers and an archive of posts—along with them. In contrast, ActivityPub requires users to create accounts on specific servers, which may impose varying moderation standards and rules

Interoperability

Both protocols emphasize interoperability. The AT Protocol enables communication between different platforms through a federated approach, allowing instances to operate independently while adhering to shared rules. This feature allows users to interact across different platforms seamlessly. Similarly, ActivityPub facilitates interaction between different instances and applications, such as Mastodon, providing a global timeline of posts from various servers. However, the AT Protocol's data portability feature enhances this aspect, allowing users to migrate their data freely between social networks, which may not be as straightforward in ActivityPub.

Control Over Identity

A notable limitation of the AT Protocol is its current reliance on Bluesky-controlled infrastructure for identity management. This centralized aspect means that users' identities are dependent on Bluesky's servers, potentially leading to a loss of control if the platform enforces bans or restrictions. In contrast, ActivityPub allows users to join different instances, each with its moderation standards, thus giving users more autonomy over their experience and identity.

Data Management and Portability

The AT Protocol places a strong emphasis on data portability, allowing users to manage their data as they see fit and transfer it between different services without loss. This contrasts with the ActivityPub model, where data migration between different servers may not be as seamless. The AT Protocol's design also supports low computational requirements for running personal data stores (PDS), enabling broader participation in the network without significant resource investment.

Future Developments and Governance

Both protocols are still evolving, with the AT Protocol aiming to solidify its governance through a formal standards process involving organizations like the IETF or the W3C. This contrasts with ActivityPub, which has already been established as a W3C standard since its introduction in 2018. The ongoing development of both protocols will likely lead to further innovations and improvements in their respective ecosystems

Developing a Social Media App with AT Protocol

The AT (Authenticated Transfer) Protocol is an open and decentralized standard developed by Bluesky, aimed at creating a more user-centric and interoperable social media ecosystem. Here is a guide on how to develop a social media app using the AT Protocol:

1. Identity and Data Repositories
- The AT Protocol provides a standard format for user identity, follows, and data on social apps.
- Users are identified by domain names that map to cryptographic URLs, securing their account and data.
- User data is stored in signed data repositories, allowing users to move their account and data freely between providers.

2. Federation and Interoperability
- The AT Protocol uses a federated networking model to sync user repositories across servers.
- It employs a global schemas network called Lexicon to unify the names and behaviors of API calls across servers.
- This enables interoperability, allowing different apps and services to understand each other's data without needing to exchange rendering code.

3. Algorithmic Choice and Moderation
- The AT Protocol allows for custom feed algorithms, giving users the ability to choose how content is displayed and ranked.
- It separates the "speech" layer (distributing authority for user posts) from the "reach" layer (content aggregation and moderation), allowing for flexible and scalable moderation.

4. Account Portability
- The protocol is designed to ensure users can migrate their account to a new provider without the original host's involvement.
- This is achieved through the use of Decentralized Identifiers (DIDs) and signed data repositories, which are independent of the user's personal data server (PDS).

To build a social media app on the AT Protocol, you would need to:
1. Implement the protocol's identity, data repository, and federation mechanisms.
2. Leverage the Lexicon framework to enable interoperability with other AT Protocol-based apps.
3. Provide custom feed algorithms and moderation tools that align with the protocol's principles.
4. Ensure a seamless user experience for account portability and migration.

The AT Protocol provides a decentralized and open framework for building social media applications that prioritize user control, interoperability, and transparency.

Implementing Short Video Features: Leveraging AT Protocol for TikTok-like Functionality

The rapid growth of short video platforms has led to a large number of user-generated short videos being uploaded every day. This has created challenges for efficient video recommendation, as collaborative filtering methods can struggle with the "cold-start" problem where new videos have difficulty competing with existing popular content.

To address this, researchers have explored content-based approaches that model the multi-modal features of short videos to better understand user preferences.

Some key points on short video features implementation using multi-modal approaches:

• Extracting and combining modality-specific features (e.g. visual, textual, audio) to represent video content, rather than relying only on collaborative signals.
• Using techniques like clustering to obtain trainable category IDs that can help bridge the gap between multi-modal feature extraction and user interest modeling.
• Measuring the varying importance of different modalities for individual users and employing techniques like pairwise loss to better decouple user multi-modal preferences.
• Deploying these multi-modal recommendation models in real-world short video platforms to improve performance in cold-start scenarios.

Overall, the research suggests that leveraging rich multi-modal video features through advanced modeling techniques can be an effective way to enhance short video recommendation, especially for new or unpopular content.

In the context of the AT Protocol, the protocol's focus on user control and transparency could be leveraged to develop short video features that give users more control over the recommendation algorithms used to surface content. The protocol's support for custom feed algorithms and decentralized identity management could enable users to choose or create their own recommendation models, tailored to their preferences.

Additionally, the AT Protocol's principles of data portability and interoperability could facilitate the development of short video features that allow users to seamlessly move their content and social connections between different platforms. This could help address the challenges of the "cold-start" problem by enabling users to bring their established social graphs and content preferences with them when trying new short video platforms.

The AT Protocol's decentralized and user-centric design principles could be leveraged to develop short video features that provide users with more control, transparency, and flexibility in how content is discovered and recommended, potentially addressing some of the challenges faced by current short video platforms.

Integrating Bluesky API: Enhancing Your App's Capabilities and User Experience

The Bluesky API, built on the Authenticated Transfer (AT) Protocol, offers a comprehensive set of features and capabilities that can significantly enhance the functionality and user experience of your social media application. Here's a detailed overview of how you can leverage the Bluesky API to improve your app:

1. Decentralized Identity Management
- The AT Protocol provides a decentralized identity system, where users are identified by domain names that map to cryptographic URLs.
- This approach ensures user ownership and control over their digital identity, allowing them to easily move their accounts and data between different providers.

2. Federated Networking and Interoperability
- The AT Protocol employs a federated networking model, where multiple independent servers work together to form a single interconnected social network.
- This decentralized architecture enables interoperability between different apps and services built on the protocol, allowing them to understand each other's data without needing to exchange rendering code.

3. Algorithmic Choice and User-Controlled Moderation
- The AT Protocol allows for the creation and sharing of custom feed algorithms, called "Lexicons," which users can choose from or even create themselves.
- It also separates the "speech" layer (distributing authority for user posts) from the "reach" layer (content aggregation and moderation), enabling flexible and scalable moderation mechanisms that are under user control.

4. Data Portability and Account Mobility
- The protocol is designed to ensure users can migrate their accounts and data to a new provider without the original host's involvement.
- This is achieved through the use of Decentralized Identifiers (DIDs) and signed data repositories, which are independent of the user's personal data server (PDS).

To integrate the Bluesky API into your application, you will need to:

1. Implement the protocol's identity, data repository, and federation mechanisms to enable user-centric identity management and data portability.
2. Leverage the Lexicon framework to provide users with the ability to choose or create custom feed algorithms that align with their preferences.
3. Develop moderation tools and content labeling services that adhere to the protocol's principles of user-controlled moderation.
4. Ensure a seamless user experience for account portability and migration, allowing users to easily move their social media presence between different platforms.

By integrating the Bluesky API, your application can offer a more decentralized, user-centric, and interoperable social media experience, empowering users with greater control over their data and online identity. This alignment with the principles of the AT Protocol can help differentiate your app in the market and attract users who value privacy, transparency, and customization in their social media experience.