...all this depends on what context it's taken in.
We started a blog about 4 months ago and we haven't seen any superior increase in retail sales yet. But then again, we're not trying to sell t-shirts through a blogging platform. We're using it as more of a way for our customers to stay on top of what's going on with us. Plus a little fun and games mixed in there to make it interesting.
If we were trying to drive sales directly, we'd take a much more viral approach to blogging, much like some of the many t-shirt review blogs do. Google "t-shirt blog" and take your pick. They are driving many loyal readers to their likes and dislikes simply by writing about it, and driving ecommerce to the sites that make the tees every day.
I'm sure you can take an example from any book to prove a point, but to say that blogging isn't driving retail sales is stupid to me.
Threadless.com sells millions of tee shirts per year, all done from a social networking platform built to enable an ongoing t-shirt competition. Their users submit the tee shirt art, vote on the designs they feel should be printed, then buy them. They have sold every shirt they have ever produced within 90 days. THIS IS UNHEARD OF in the retail business. A big part of this is because people are able to BLOG about their opinions to their friends, other customers, the administrators, etc., from within the site. It's genius.
Imagine if all you had to do was look on your own retail site to see what the pulse of your customers were thinking... would you be able to market to them better? serve them better? engage them better? Of course you would... All that would lead to SELLING better.
I don't know how Tom Cox could engage his customers by getting them into golfballs any more than what they're already doing. Namely, hitting them into man-made ponds. Maybe he should try selling something a little more creative, then people would have something to get excited about. Then he'd have a different opinion?
Ah well, who knows...