Please also note that despite the above disclaimer, the current Bulletin web-overlord, A.L. Sirois , has combed through this page in August of 2001 and repaired the busted links.
Nobody really knows whether self-promotion helps sell books.
There are success stories, and there are the other kind. There's no clear evidence, either way. It certainly can be a strong piece in the mix of promotional tools. In the first two years my page was on the Web, I had email from perhaps two dozen people indicating that they'd bought my books as a result of the sample chapters there. In the first month after the release of my most recent book, I heard from at least a dozen more.