Previously, every time someone has posed the question “Should I make my blog part of my business domain, on a subdomain, or as a different domain altogether?”, I have said “Put it on your main domain, this will allow you to share pagerank between your blog and your business”. What can I say, I really wish that circa June, 2007 I had known enough about my own advice to take it. :)
Steph of real estate software fame recently posted a link to a tool which will tell you your pagerank for different domains after the currently-in-progress PageRank update gets pushed to all the Google clusters. At present, it seems that Bingo Card Creator is a PR4, which is neither terrible nor anything to write home about after I’ve spent a good deal of time trying to build up some links for it. This blog, on the other hand, is PR5 — solely due to people deciding what is here has value and linking it from their blogs (and other content aggregators which are spiderable, such as Slashdot or the WordPress front page).
The difference between PR4 and PR5 is a whole lot of searches, particularly for low-competition niches like, well, Dolch sight words. I now get an absolutely insane number of people who search for my very favorite search terms and come *here* first, then follow the link to my actual product site. This is utterly insane not because of the magnitude, but because I know I must be losing a huge percentage of the potential traffic there. Ah well, lesson learned. Don’t let it happen to you!