Very cool. Reason I ask is at first glance the header "Search the Internet" to me, implies you are searching the entire internet. It sounds like a more appropriate header would be "Search the obsecure Internet"
Internet arguably doesn't even have a size. You can construct a website that's like n.example.com/m which links to '(n+1).example.com/m' and 'n.example.com/(m+1)', for each m and n between 0 and 1e308.
Dunno about the others, but my crawler has a set depth it will crawl. It'll BFS for like 1000-10000 documents depending on some factors.