Sometimes I follow eBay auctions to get an idea of what items are selling for. I've noticed that eBay will sometimes show the number of other followers on an auction and sometimes not. I guess there is a number threshold that has to be crossed to have it displayed on the actual ad.
I found a website that will do this for you: watchcount.com
You can either enter keywords of the ebay item number and you get a result like this (click on it to go to the site):