Hi
if you mean
http://db.tidbits.com/ - I didn't get any popups in a few minutes of browsing there, this without any blocking software. If you're seeing the very same ad popup window from differing sites, then it'd sure be worth looking at whether or not your mac or router or isp is using some rogue dns server.
DNS -
Domain Name System
it translates domain names meaningful to humans into the numerical (binary) identifiers associated with networking equipment for the purpose of locating and addressing these devices worldwide. An often-used analogy to explain the Domain Name System is that it serves as the "phone book" for the Internet by translating human-friendly computer hostnames into IP addresses. For example, www.example.com translates to 192.0.32.10.
to borrow from wiki.
DNS servers can be chosen in your router or in your mac at System Preferences-Network-Advanced-DNS tab, If no special dns servers are selected, your router will usually accept the isp's suggestion, so you'll be using theirs, for better or for worse.
The most common place for any 'rogue' dns to be set, is in System Preferences-Network-Advanced-DNS tab... look there on your mac, and see if any numbers are visible. Copy them & paste here, then we'll know what's going on.