I actually hacked up a feed-horfer that populated an IMAP account some years ago. IMAP gets you like 90% of the way there.
There's no facility for updating items, that was about the only thing really wrong with it from the end user perspective, assuming you are okay with storing the full text of tens of thousands of items when you will only read 2% of them.
But I don't see anything wrong with that in an era where even our phones have 64GB of storage...
EDIT (my touch device over zealously submitted): but IMAP isn't the right solution, even though it could work, and work better than google reader even. A RSS sync system really shouldn't require the user to download all the items and then sync against their own copies of them---it should be able to sync what has been read[1] based on the canonical URI of the item, with some intelligence to grok the mod dates to track updated items. Storage isn't a problem anymore for mostly-textual content, but mobile latency and data caps are.
[1]: and, in my opinion, notnjust what has been read, but what has been flagged, labeled, tagged, reposted, liked, hated, and／おr assigned whatever other arbitrary metadata
It seems like it gets you far enough. A custom IMAP client can just not download anything locally (just grab the headers and cache content of anything you've read), plus UI niceties (click on header to navigate to page). IMAP allows you to use this reader on platforms where no friendly client exists yet.
Oh yeah, totally; by having to "download all the items" I meant on the server. Assuming your were importing feed to an IMAP server that you owned, and reading feeds with a standard IMAP mail client. (Sounds kludgey, but really did work better than 90% of solutions to date.)
But if you mean a provider providing IMAP access to RSS feeds, that could work great. I don't know how to deal with updated items, but there is probably a way, especially if you had a custom client for key platforms. And 2nd tier platforms could still use an IMAP mail client.
There's no facility for updating items, that was about the only thing really wrong with it from the end user perspective, assuming you are okay with storing the full text of tens of thousands of items when you will only read 2% of them.
But I don't see anything wrong with that in an era where even our phones have 64GB of storage...
EDIT (my touch device over zealously submitted): but IMAP isn't the right solution, even though it could work, and work better than google reader even. A RSS sync system really shouldn't require the user to download all the items and then sync against their own copies of them---it should be able to sync what has been read[1] based on the canonical URI of the item, with some intelligence to grok the mod dates to track updated items. Storage isn't a problem anymore for mostly-textual content, but mobile latency and data caps are.
[1]: and, in my opinion, notnjust what has been read, but what has been flagged, labeled, tagged, reposted, liked, hated, and／おr assigned whatever other arbitrary metadata