del.icio.us is a social bookmarking website the primary use of del.icio.us is to store your bookmarks online, which allows you to access the same bookmarks from any computer and add bookmarks from anywhere, too. On del.icio.us, you can use tags to organize and remember your bookmarks, which is a much more flexible system than folders.
The delicious user for Twitter is already claimed.
However, this is what I would look for, I would like to do the following:
@delicious URL #tag #tag
This would ideally create a bookmark for me in delicious. I have a RIA twitter app open all day and this would be a great interface to have.
Obviously, the backend integration on delicious would require entry of a Twitter username tied to the delicious account so that you do not get random spam but I think it would work very nicely.
The Delicious Bookmarks plug-in is amazing, but I'd like to see some way to sync bookmarks with Firefox Places. Ideally, this would happen automatically, but if server calls and load are a problem, it would be nice to schedule it once a day / week or just have an on-demand option.
When I bookmark a page I want to make sure that the content remains saved (someplace) regardless of whether or not the real webpage disappears for whatever reason. This has happened to me a lot using delicious and it's the only reason I use Yahoo bookmarks. (Yahoo owns your company - can't you borrow some of their guys?)