Add the possibility to read an URL later
When an article contains a link and I am reading it offline, I would appreciate the possibility to mark the linked URL for reading later (a fake RSS feed "Read Later"). When I get online and the feed sync starts, full HTML of the URLs in the "Read Later" feed would get downloaded for offline read.
If the Gfeeds app would accept "sharing" an URL into it, it could be added to "Read Later" list as well and the user could "share" the URLs directly from a browser (using an add-on like "Open with" for Firefox).
Both these features would make Gfeeds a great tool for learning.