I find people only sign if i make a big point of it during the gig. I find it hard enough to remember to plug the CDs, radiobritfolk, the next gig etc and often I forget to tell people about the list. Some gigs no-one signs. Possibly people know they can see where you are playing on your website so don't feel a need to go on the list. We get about 800 hits a week, so maybe that is what people prefer.