Absolutely! The idea was suggested by Andrew, 2W0MGB, one evening as we were talking about all the different sizes and the confusion caused by different companies calling the same battery by different names, also the difficulty in cross referencing as many suppliers didn't have a full list. The Equivalents page still doesn't have a full list, but I've certainly got more than most!
I placed a link on Wikipedias' Battery sizes page to assist people finding more than was available on that page and the referrals started to come in from there. Then the search engines "picked up" the details pages as well as the main equivalents page.
I have had feedback from some saying how useful it is, others with additions/corrections (we all make mistakes!) and even an email from a local government employee in America asking if I knew the ANSI (American National Standards Institute) numbers for some batteries that I had not (yet) listed! (she was in the right country to contact ANSI direct!)
Some visitors to the equivalents do "look around" the site so it does get people looking at us to see who we are and what we are about.
Updated 11 Dec. 2008: Since I first wrote this answer there have been links and mentions placed on:
Also I can report that the Battery Equivalents section is the most visited area of the site by far!