First Icon is Digg (
Digg / about us)
2nd Icon is Del.isio.us (
del.icio.us/about)
3rd is Technorati (
Technorati: Home)
4th is Furl (
LookSmart's Furl - features)
They all have varying functions but the main theme is either social networking (you can submit links from
AIUK to be read by others) or link storing (you can store
AIUK links in your account to keep them all in one place). You can find out more about each of them by using the links above.
For
AIUK, each link or thread submitted to one of the above means better Search Engine Optimisation for
AIUK (e.g. the more pages that link to
AIUK the further we get up the search engines and the easier we are to find).