Twenty Links is a child theme of Twenty Ten for WordPress. It turns your WordPress site into a bookmark repository that, coincidentally, looks a lot like the old Delicious.
The Top [n] Tags widget is built in to the theme. The Combine Tags widget shown on my links site comes from Scribu’s excellent Query Multiple Taxonomies plugin.
You can use the built-in Press This bookmarklet to save links to your site. The theme includes a few customizations for that screen to turn off things you probably won’t use (the Save Draft button, the Categories box). Visit your Tools page in the Dashboard to set up the bookmarklet.
The theme uses a responsive layout that automatically rearranges itself for mobile devices.
Importing from Delicious
Grab the Delicious XML Import plugin to set up your own link archive. The importer has a few options so it can support other Delicious-like themes. If you plan to use Twenty Links, you should import your links as posts and use tags rather than categories.
0.6.2: Several bugs fixed: incorrect URLs for subdirectory installations (props aldolet), endless link tag in trashed post notice, bad layout on “not found” pages.
0.6.1: Tiny update to remove the plus links when viewing the home page, since they don’t work there anyway.
0.6: Mobile version. Added the post count and the RSS button to the tag filter area. Fixed alignment problems with the new plus sign links. Added styles to turn off unneeded things (Save Draft button, categories) in Press This. Fixed autocomplete for non-logged-in users. Localization.
0.5: Tag autocomplete! Little plus signs inspired by Gary! Fixed the hard-coded tag base. Incorporated a bit of code from Bill that takes you straight to the link rather than the single archive page.
There’s a combined forum for the importer and the theme over on my support site. Please report problems there.