UPDATE: there is now an IdentityBurro project page
You are looking at the page of xyz on flickr and you would like to see xyz‘s bookmarks on del.icio.us?
Or, you are on the technorati profile page of abc and you would like to see abc‘s photos on flickr?
Well, if one of these desideratas has been in your mind before, you now have it!
Enter Identity Burro (or IdentityBurro), a GreaseMonkey extension that inserts, in the profile page of user xyz on flickr or del.icio.us or technorati, the link to the profile pages of user xyz on flickr and del.icio.us and technorati. Your social sites are now more social!
See the screenshots.

Still with me? Then I guess you might want to install:
   Current Version: Identity Burro v0.1

At the moment there is nothing better I can do that assuming an user has the same nick on every site: I assume xyz@flickr is xyz@del.icio.us and xyz@technorati. I know this is by no means guaranteed to be true (or desirable). I hope (and ask) that one of this social sites will soon let its users to enter which are their nicks on other sites. In this way I would be able to get this information and put the correct links when xyz@flickr is called abc@del.icio.us.

And of course, as you can see by the name of the extension, inspiration for this extension came from the mighty BookBurro extension, whose creator Jesse I just met few days ago at the AAAI 2005 conference in Pittsburgh.
The code is released under a Creative Commons “Attribution-ShareAlike 2.5” licence (since Book Burro was released in this way and the shareAlike option didn’t really give me a chance to change licence for a GPL).

If you like, you might want to let me know if it works in the buggy browser, I mean, Internet Explorer.
Todo:
# when expanded, part of the unexpanded interface (buttons and icons) remains in background, more transparent. understand why and fix it
# when expanded the “expand” icon should become a “shrink” icon (the arrow in the other direction).
# some CSS properties are inherited from the current site, so that for example, the extension looks a bit different in flickr and in del.icio.us. Understand which are the properties of which elements and overwrite them (surely the background of some elements is inherited).
# adding more social sites, for example, webjay, citeulike, last.fm, audioscrobbler, furl, wist, blogmarks, 43things, tagsurf, upcoming, jots, podcast, consumating, rojo, bloglines, smugsmug, bookswelike, kinja.

Leave comments to this post for communicating with me about the extension.

Screenshots

Del.icio.us with Identity Burro not expanded (all icons are clickable anyway):

Del.icio.us with Identity Burro expanded:

Technorati with Identity Burro not expanded (all icons are clickable anyway):

Technorati with Identity Burro expanded:

Flickr with Identity Burro not expanded (all icons are clickable anyway):

Flickr with Identity Burro expanded: