All messenger programmes have exploits, especially AOL and ICQ though MSN has had it's share too. Any popular programme will have exploits, it's not just limited to messengers or even IRC. Look at the Unix mailserver, Sendmail. It's got more holes than a lump of Swiss Cheese. Why? Because it is popular. People who want to cause trouble on the net will target popular programmes because that is the most profitable way of doing damage.
