I have a lot to say about this and all of it is good. The generation of Silver Age legends will not be around to sign their books forever and it only increases the value of the collectibles they created when the comics are signed and authenicated. And it allows the artists to put a little money (and it's very little) in their pockets during their twilight years. So I am all for it and investing my time to make this happen.
I will be the CGC witness for upcoming signings with Joe Kubert, Gene Colan, Rich Buckler (who created Deathlok), Herb Trimpe, Michael Netzer, and Russ Heath. If I were you, I'd get in on these.