yes, a clique is a well-connected subgraph --- where a graph is a connection of "verticies" (in this case lj-users) connected by "edges" (in this case, the friend-of relationship), and a "well-connected" graph is one where every vertex has an edge connecting it to every other vertex. Finding an "approximate" clique would be very interesting, but I think much more difficult from a computational perspective. The 'meme' was started by my friend hukuma, a graduate student in computer science at Berkeley, and I assumed that's how you found it.