For example, if you go to List Manager > Add Lists you could add 'hijacked' from http://www.iblocklist.com/lists.php - this list includes 'know' hackers, bot-nets, scammers and spammers etc. I'm sure you can understand the benefits there. The Anti-P2P lists also block companies and organizations that scan P2P users, blocking these will again help increase a Bitcoin users overall anonymity and PC security, including that of the Bitcoin P2P network.

These lists are compiled by individuals and a community that has a real interest in protecting computer networks and P2P users.