It seems the old Shareaza website was hijacked by a group referring to itself as Discordia Ltd, and a copycat version of the site has taken its place, including making available malware/spyware "Shareaza v4" which requires your personal information (including your credit card number) and apparently tracks your searches, the purpose of which is currently unclear.
If you do use Shareaza, please update your bookmarks to point to the new website, here: http://shareaza.sourceforge.net/ . The real official version of Shareaza is 18.104.22.168.
More information about this hijack/scam is available in their forums, here: http://www.shareazasecurity.be/forum/viewforum.php?f=46 .
If you have already installed the malware program calling itself "Shareaza v4", there are instructions on removing all aspects of this program here: http://www.shareazasecurity.be/forum/viewtopic.php?f=46&t=450 . Please note that simply uninstalling the program will not remove all the tracking capabilities.
Anyway, after finding this out, I wanted to share this information, in hopes to avoid anyone here getting taken in by this scam.