Which Social Bookmarking?

Since changes to Firefox made exporting bookmarks from Ice* a pain, I’m trying to find a social bookmarking site that is:-

1. run on free software
2. provides RSS feeds of new additions (pref. RSS-1, but any RSS is OK)
3. provides all my bookmarks for download/backup in some easy format (even an HTML page would be fine)
4. at least lets me view without javascript, so I can use my bookmarks from my smartphone easily

Is that so much to ask for? I’d probably add whatever is used the the blog hosting platform. So far, I’ve looked at:-

• delicious, furl, digg, stumbleupon, technorati, facebook – the blog host links these from every post but none of them look like free software and most make it hard to download bookmarks;
• Reddit – I’m not sure that CPAL is a free software license because of the Original Developer oddities;
• Magnolia – I thought it was free but I can’t find the licence now;
• Sitebar – close but javascript needed to view.

I’m wondering about downloading something like b. or insipid and parking it on software.coop somewhere. Am I missing an obvious candidate?