I can't remember whether this came up in a post on the Board, or whether I was in some other forum, but the ones to avoid 
like the plague are:
AOL
MSN
Hotmail
Yahoo
These "providers", as I understand it, lay claim in the fine print to all your material on their servers as their property including your commercially-sensitive information and intellectual property.  When challenged, apparently they say that it's to keep them out of legal hot water, and that they don't, in fact, invade your files at all.  You'd use them of course.  Yeah, right.
Note that the wording they use seems innocuous, but Sparteye or Scribbler or any half-trained legal eagle would apparently spot the problems pretty much right away.  This doesn't include me.
No doubt there are other ISPs out there who will steal anything which isn't nailed down.  Using a webmail provider is, however, a major risk.   I research ISPs as best I can, myself ...   
