Here is a list of different Social Bookmarking sites that have RSS feeds and how to format the syntax without having to login or access their site.

Why do you need this list?

A quick and easy way to promote your bookmarks (aka links to your pages) via rss.

What can you do with this?

Use the feed with your social bookmarking account userid and a feed with a keyword tag in your niche and create a custom feed or content to a blog.

You can bookmark your feed url in different social bookmarking services or accounts.

Use it like any other rss feed.

The feeds are light on content but rich on links back to your site if you are using USERID feeds and have bookmarked some of your own sites.

If you are using the KEYWORD make sure it is a general category like a tag, not a long tail search term.

http://www.blinklist.com

http://www.blinklist.com/tag/KEYWORD/rss.xml

http://www.blinklist.com/USERID/rss.xml

http://www.bibsonomy.org/

http://www.bibsonomy.org/rss/user/USERID

http://www.bibsonomy.org/rss/tag/KEYWORD

http://del.icio.us

http://del.icio.us/rss/USERID

http://del.icio.us/rss/tag/KEYWORD

http://del.icio.us/popular/KEYWORD

http://del.icio.us/rss/USERID/KEYWORD
- great for making a feed of a specific niche of bookmarks for a user

http://furl.net

http://rss.furl.net/member/USERID.rss

http://rss.furl.net/items.rss?topic=KEYWORD

http://ma.gnolia.com

http://ma.gnolia.com/rss/full/tags/KEYWORD

* includes thumbnail images of websites. Great if you need a directory style look. Here is a sample of the feed on a WordPress blog:
** not a sb site ** http://englishhorn.info/testsb/ ** not a sb site **

http://ma.gnolia.com/rss/full/people/USERID

http://ma.gnolia.com/rss/full/terms/DOMAIN
- another great feature to use is the feed for all the pages of a domain bookmarked

http://blogmarks.net

http://blogmarks.net/api/user/USERID/marks?format=rss

http://blogmarks.net/api/marks/tag/KEYWORD?format=rss
- includes thumbnail images of website

http://www.simpy.com
http://www.simpy.com/rss/user/USERID/links/
http://www.simpy.com/rss/user/USERID/links/KEYWORD
They use ads by Pheeds embedded in their RSS feeds.
Depending on your RSS system, it can make a mess of your posts.
Not recommended so use with caution.

The above are my favorite social bookmarking sites simply because they are supported by the main tools like Auto Social Poster and Bookmarking Demon as well as have RSS capabilities.

I didn't include sites that the RSS features were not working when tested or the sites that don't support RSS feeds.

If you haven't started to use social bookmarking, the above sites are a great start.