# Discussion: Solid vs. ActivityPub **URL:** \ **Category:** Connection to Other Initiatives\ **Created:** [February 25, 2020, 4:52pm UTC](https://forum.solidproject.org/t/discussion-solid-vs-activitypub/2685 "2020-02-25T16:52:24Z")\ **Posts on this page:** 1\ **Showing post:** 35
**Author:** ![aschrijver](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.solidproject.org/aschrijver/32/463_2.png) [@aschrijver](https://forum.solidproject.org/u/aschrijver)\ **Post date:** [March 11, 2021, 5:07pm UTC](https://forum.solidproject.org/t/discussion-solid-vs-activitypub/2685/35 "2021-03-11T17:07:19Z")
The topic of [Decentralized Twitter (Dewitter) App Scenario](http://forum.solidproject.org/t/decentralized-twitter-dewitter-app-scenario/4082) led me to write this post… When talking about decentralized Twitter, we have that in the form of Mastodon, Pleroma and [other microblogging apps](https://git.feneas.org/feneas/fediverse/-/wikis/watchlist-for-activitypub-apps#social-networks-microblog-apps) that federate together in the Fediverse. Some more combinations of Solid + ActivityPub to ponder, maybe. In a [recent toot](https://boseburo.ddns.net/objects/29dffafd-55a2-410a-bffe-4aaad9d6d14c) and [another follow-up](https://m.tzyl.nl/@ton/105752273529449833) I discovered how incredibly much space is needed by server instances to save timelines / social graphs. For instance, a single-user installation running for 2,5 years requiring 821 MB and a 14 user instance with DB size of 4 GB. Interesting is that _more users per instance requires less storage space per user_. As [@masto.host](https://mastodon.social/@mastohost) explained to me: > In terms of sizes scaling with the number of users, usually it doesn’t scale linearly because if you have 10 users and 5 of them follow remote account X. The posts from account X are only federated/stored once. So, in general the larger the number of users the smaller the database space per user. > > Obviously depends on usage. If you have a closed Mastodon server where the users down follow remote users or a small number of remote follows, this isn’t the case. In the future Fediverse will probably move from a federation model to hybrid decentralization, supporting both federated and p2p nodes. This move will be accompanied with support for content-addressing (see e.g. [ERIS](https://gitlab.com/openengiadina/eris/-/blob/main/doc/eris.adoc)). There are two things I wonder about: - What are experiences with Solid in terms of storage space and also amount of requests to reconstruct social graphs (performance), esp. when having a lot of following/followers and you are an active communicator. Interesting to hear from SAFE as well (@happybeing?). - Thinking of combinations with federated ActivityPub-based solutions that would lead to smaller db sizes on the server instances, and more control / ownership over own data. Especially the Direct Message functionality of Mastodon / Pleroma can be improved. This is private data (only select audience can see it), but if I clean up my own DM inbox (delete messages) via federation it leads to similar deletion of messages in the inboxes of those people tagged in the DM discussions. --- _[View the full topic](https://forum.solidproject.org/t/discussion-solid-vs-activitypub/2685)._