Well, after some attempts, I finaly took the self-hosted route (which was absolutly not planned at the time of the question writing) with a very good project, which is a kind of delicious self-hosted clone : Shaarli. As one may note by looking at the very good documentation page all the features are present, and some other are nice additions (feature list borrowed from site)
Minimalist design (simple is beautiful)
Dead-simple installation: Drop the files, open the page. No database required.
Easy to use: Single button in your browser to bookmark a page
Save url, title, description (unlimited size). Classify links with tags (with autocomplete)
Tag renaming, merging and deletion.
Automatic thumbnails for various services (imgur, imageshack.us, flickr, youtube, vimeo, dailymotion…)
Automatic conversion of URLs to clickable links in descriptions. Support for http/ftp/file/apt/magnet protocols.
Save links as public or private
1-clic access to your private links/notes
Browse links by page, filter by tag or use the full text search engine
Permalinks (with QR-Code) for easy reference
RSS and ATOM feeds (which can be filtered by tag or text search)
Picture wall (which can be filtered by tag or text search)
“Links of the day” Newspaper-like digest, browsable by day.
“Daily” RSS feed: Get each day a digest of all new links.
PubSubHubbub protocol support
Easy backup (Data stored in a single file)
Compact storage (1315 links stored in 150 kb)
Mobile browsers support
Can import/export Netscape bookmarks (for import/export from/to Firefox, Opera, Chrome, Delicious…)
Brute force protected login form
Protected against XSRF, session cookie hijacking.
Automatic removal of annoying FeedBurner/Google FeedProxy parameters in URL (?utm_source…)
Shaarli is a bookmarking application, but you can use it for micro-blogging (like Twitter), a pastebin, an online notepad, a snippet repository, etc.
You will be automatically notified by a discreet popup if a new version is available
Pages are easy to customize (using CSS and simple RainTPL templates)