Microblogging with RSS

So what do you need to mimic Twitter over RSS?

1. An RSS reader, ideally one that presents posts in truncated form, in a reverse-chronological mixed stream
2. Optionally, a cloud-based feed-crawler/reader service to do the heavy lifting and sync your position across multiple devices
3. A place to store your posts online
4. A place to serve a feed of your posts

You really only need #1 unless you want to be able to say things too, in which case you need #3 and #4.

Any existing Feedly-style service could provide the #1/#2 combo with just a little UI work.

Any blog could provide the #3/#4 combo. Undoubtedly some that are customized for microblogging would emerge if this becomes a thing.

Or, the Feedly-style service could add support for #3 and #4 without too much trouble.