Hey! I'm a newbie, and just started getting interessted in fanmail.

I'm a little confused, and was wondering about Via Venue's. I think I know what they are, so I'm going to say it and I want you to please correct me if I'm wrong. Are they like temporary addresses for celebrities for like when they're at concerts and stuff? Do people send pictures there because its more likely that they'll be actually autographed instead of a copy? Sorry if it's a stupid question, but I honestly don't know. Thanks!