I just had a guy the other day who wanted to trade blog links, said his blogs were pretty new because the blogs he use to have were on blogspot and they got hacked. Think there was a post on this board about another person that had their blogspot blogs hacked by a LL owner.
Dont see it as a rule just against blogspot blogs, as RawAlex said, it's free hosting and usually not durable. I've listed some, but only from people I know.
I agree on thumbblogger somewhat, it's still free hosting though, they are not paying for hosting so they dont have an big incentive to keep it going.
ronnie