Waxy.org demonstrates how to use Google’s Usenet archive to track memes, in this case, the “All Your Base’”meme.
This is precisely what I intended to do with memewatch.com. I think the phrase I first wanted to plot this way was “six degrees of Kevin Bacon.”
Here’s the tricky thing: not all memes equate to phrases. For example, one meme I’d love to track is the cynical use by politicans of the phrase “…for the children,” and perhaps the ironic meta-use of that phrase as criticism of said politicoes. But simply searching on “for the children” won’t capture those contexts.