In short Sigs have been VERY well known for numerous benefits from SEO all the way to even Sales and Traffic! I've experienced both but the problem is that you cannot view the stats such as how many people are viewing your links and how many actually click through!
Wouldn't it be great if the warrior forum could have some script to check such stats maybe for small fee as an added feature or bonus to members. Would definitely be great to help with marketing.
Just thought I'd toss out this suggestion.