I don't think it will make much a difference to yahoo as i personally think aol have nothing to give......I don't think yahoo would be gaining anything in that.
The AOL is pretty good search engine and if yahoo and AOL merge then both of them have enough to offer each other. Their merger could create for Google. lol
Absolutely, it could be possible since yahoo has rejected microsoft's bid and will look for other offers too, aol has a good chance of buying out yahoo, if they are indeed interested.