We can't block JS files with ad blocking CSS (alas).
That bookmarklet give me a blank wyciwyg page with the following source: <html><body><dl></dl></body></html> If you refresh enough on the following link, you're bound to get an occasional Flash ad. I get them ~1/8 times with a shift-reload. Only a few of the ads hang Camino, but those seem to repeat quite a bit.
I've been shift-reloading that page for 10 minutes and haven't seen a single ad, let alone a flash one. (There is a blank iframe there where an ad would go, src=http://deLB.mspaceads.com/html.ng/site=myspace&po sition=leaderboard&page=11013005&rand=468490599&friendid=294566860) In that vein, if it's really the 2nd JS that controls that ad, it puts up an iframe beginning with a src=http://de**.mspaceads.com/ (where ** are some two-capital-letter combos) We're already blocking mspaceads.com for imgs; if we do the same for iframes, that should probably should solve the problem.
That's funny. On the first load I got an ad. In any case, looking at the JS, I think Smokey's right. Updating summary to reflect what we assume is needed to fix this, which is blocking iframes from mspace.com.