] This is the web site for the Erdös Number Project, which
] studies research collaboration among mathematicians.

Paul Erdos was a famous mathematician who authored and/or co-authored over a thousand different papers. So famous was he, that his co-authors gained fame just for having their names on the same paper as he (which gave them "Erdos 1" status). So famous were those co-authors, that others gained fame for co-authoring a paper with someone who had once co-authored a paper with Erdos (which gave the co-co-authors "Erdos 2" titles). And then people who co-authored with "Erdos 2" people became "Erdos 3", and so on. Sort of like the Degrees of Kevin Bacon, but in the academic world.

I was recently approached about co-authoring a paper with someone who's an Erdos 3, which would make me an Erdos 4, if it happens. I'll probably do the paper, regardless of the Erdos-ness of it. Having never heard of the numbering scheme before, it doesn't matter that much to me. But still, I found it worth meme-ing for the day. :)