The Webheads "gallery" (the one here: http://vancestevens.com/papers/evonline2002/webheads_evo.htm) has become well-known within certain distributed learning networks. Webheads arose in a Web 1.0 era and its webmaster-maintained artifacts have long been overtaken by Web 2.0 ones.
I stumbled on Twitter Mosaic http://sxoop.com/twitter/ via one of Hala Fawzi's blogs: http://englishonlinects.blogspot.com/.
Voila! The new Webheads gallery (happily most of those spam followers seem to have been filtered out when their accounts were suspended; I wonder if this updates live :-). Incidentally if you don't want someone appearing in your mosaic you can click on that person's avatar to delete it from the final result, simple.
This visualization has allowed me to see my personal learning network in a new light. This is the first visualization that I've become aware of where I could picture my network so clearly. Each thumbnail has a mouse-over that not only reveals a Twitter user name, but lets you click on the user name and pull up a Twitter profile. At that profile I can have a look at the follower's posts and if I think I'd like to see more posts like that, I can conveniently follow that person right then and there.
Anyone can do the same. That is, you can pull up my network in this way (you don't need my password) and I can pull up yours. So if I want to see who is in your network I can generate a mosaic like this and I can click on people and follow them if I have that much respect for your network that I would go to that trouble (and I just did that with someone in my network to test it out, respect!).
A final comment, I've discovered that at least two people in my network are no longer of this world. That's sad on one level, but on another, there's more respect again in networks where people can remain virtually after they have gone, where the work they have accomplished lives on in a sort of immortal online presence.