| Architecture | 
Centralized | 
Centralized UI, Decentral Storage | 
Decentralized (ActivityPub) | 
Centralized (Self-Hosted) | 
Decentralized (ActivityPub, Diaspora) | 
Decentralized (ActivityPub) | 
Decentralized (Diaspora Protocol) | 
Decentralized (ActivityPub) | 
Decentralized | 
Decentralized (ActivityPub) | 
Decentralized (Nostr Protocol) | 
Decentralized (Self-Hosted/Clustered) | 
| User Authentication | 
Username / Password | 
Username / Password | 
Password | 
Password | 
Password-based | 
Password | 
Username / Password | 
Username / Password | 
Username / Password | 
Password-based | 
Public/Private Key Pair | 
Passwordless via Email Tokens | 
| Content Synchronization | 
Central server handles all | 
Planned for decentralization | 
Federated, server-to-server | 
Manual or plugin-based | 
Federated, server-to-server | 
Federated, server-to-server | 
Federated, pod-to-pod | 
Federated, video sharing | 
Federated, across hubs | 
Federated, server-to-server | 
Client-driven, no central server | 
Clustered, content synchronized | 
| Post Length | 
280 characters | 
300 characters (subject to change) | 
500 characters | 
Flexible, Markdown supported | 
No strict limit, Markdown | 
No strict limit, Markdown | 
No strict limit, Markdown | 
Video-centric, long descriptions | 
No strict limit, rich text | 
No strict limit, MFM formatting | 
No strict limit, depends on clients | 
Markdown posts, no strict limit | 
| Media Support | 
Images, Videos, GIFs | 
Images, Videos | 
Images, Videos, Audio | 
Images, Videos, Customizable | 
Images, Videos, Audio | 
Images, Videos, Audio | 
Images, Videos | 
Videos, Images | 
Images, Videos, Files | 
Images, Videos, Audio | 
Depends on client implementations | 
Images, Videos, Custom Media | 
| API Access | 
Restricted, Paid for full access | 
Open API for development | 
Open API for development | 
Open API, customizable | 
Open API, extensible | 
Open API, extensible | 
Limited API | 
Open API for development | 
Open API, extensible | 
Open API | 
Open, no central API | 
Open API for development | 
| Clustering & Federation | 
Not applicable | 
Developing AT Protocol for this | 
Federated by default | 
Not inherently, but can be extended | 
Federated, plugin support | 
Federated, server clusters | 
Federated, pod clusters | 
Federated, instance clusters | 
Federated, hub clusters | 
Federated, server clusters | 
No clustering, peer-to-peer | 
Clustered, manual source setup | 
| User Control Over Algorithms | 
No direct control, algorithmic | 
Users can select algorithms | 
Chronological by default, customizable | 
None by default, customizable | 
Limited, plugin-based | 
Limited, server configuration | 
Limited, pod configuration | 
Limited, by instance admin | 
Extensive, through hubs | 
Customizable by server admins | 
Client-driven, no algorithms | 
Chronological, searchable | 
| Privacy & Data Ownership | 
Limited user control | 
Emphasis on user data control | 
Strong emphasis on user control | 
High control, self-hosted | 
Strong emphasis on user control | 
Strong emphasis on user control | 
Strong emphasis on user privacy | 
Strong, instance-specific policies | 
Strong, with many privacy options | 
Strong, instance-specific policies | 
High, self-sovereign data | 
High control, self-hosted or clustered | 
| Moderation | 
Centralized, can be controversial | 
Automated with user control | 
Server-specific, community-driven | 
Customizable by the admin | 
Server-specific, community-driven | 
Server-specific, community-driven | 
Pod-specific, community-driven | 
Instance-specific | 
Hub-specific, community-driven | 
Server-specific, community-driven | 
No central moderation, client-based | 
Admin-based, configurable | 
| Interoperability | 
Limited | 
Planned with AT Protocol | 
With ActivityPub protocol | 
Limited, depends on plugins | 
High, with multiple protocols | 
High with ActivityPub | 
Limited to Diaspora network | 
With other ActivityPub platforms | 
High, with multiple protocols | 
With other ActivityPub platforms | 
Interoperable via Nostr protocol | 
Limited, JSON/XML API | 
| Search Functionality | 
Advanced, algorithmic | 
Basic, customizable feeds | 
Server-specific, less advanced | 
Basic, depends on setup | 
Basic, server-specific | 
Basic, server-specific | 
Basic, pod-specific | 
Basic, instance-specific | 
Advanced, hub-specific | 
Advanced, server-specific | 
Depends on client implementation | 
Advanced, chronological & by search | 
| Monetization | 
Ads, Premium features | 
Not specified, open-source ethos | 
Donations, no ads by default | 
Free, can be monetized by host | 
Donations, no ads by default | 
Donations, no ads by default | 
Donations, no ads by default | 
Donations, no ads by default | 
Donations, no ads by default | 
Donations, no ads by default | 
No central monetization | 
Not specified, customizable | 
| User Migration | 
Difficult to export data | 
Designed for portability | 
Data can be moved between servers | 
Depends on implementation | 
Data can be moved between servers | 
Data can be moved between servers | 
Data can be moved between pods | 
Data can be moved between instances | 
Data can be moved between hubs | 
Data can be moved between servers | 
User controls data, no migration needed | 
Data import from X, manual setup | 
| Running Own Server | 
Not applicable | 
PDS Limited to 10 users, requires subdomain, DNS setup, no UI | 
Full server with UI, unlimited users | 
Full server with UI, customizable | 
Full server with UI, customizable | 
Full server with UI, customizable | 
Full pod with UI, customizable | 
Full server with UI, video focus | 
Full hub with UI, customizable | 
Full server with UI, customizable | 
No central server, client-driven | 
Full server with UI, JSON/XML data, clustered | 
| Direct Web Access | 
Via official app or website | 
No direct web access for PDS, needs Bluesky app | 
Direct via domain/server | 
Direct via domain/server | 
Direct via domain/server | 
Direct via domain/server | 
Direct via domain/server | 
Direct via domain/server | 
Direct via domain/server | 
Direct via domain/server | 
No central server for direct access | 
Direct via domain/server with JSON/XML API |