These would be particularly handy for those of us who speak at different type of user group meetings. I give semi frequent talks for local Debian / Ubuntu user groups, and sometimes talks on how to ensure compliance with OSI approved software licenses at offices (all for free).
This is something I keep completely separate from my day job, mostly because it's for my own enjoyment and I don't see why promoting them would help anything. I don't want to sell someone a VPS, I want to help them avoid conflicts with various versions of the GPL.
SO, on the other hand, is a great companion resource to almost everything that I discuss, or probably ever would discuss.
I'd be all for being stocked with professionally printed cards and a nice cache of stickers to give away. I gave away most of my SO stickers when I got them, people really liked having something cool to put on their laptop.
Did anyone who received a sticker or a million unicorn bucks become an active contributor? I really don't know, I don't think there's a way to even track it. The point is, it helped me do something I normally do a little bit better - while also promoting a resource I could feel good about promoting.
Addendum
I'm all for moderatorname@stackoverflow.com
, however I don't want yet another POP/IMAP account to manage. This is for a couple of reasons:
- My mail client is already beginning to choke on less powerful computers (netbook / mobile)
- Sometimes I have to use the uber expensive 3G network to get mail
- Just one more login to remember / set up again if I change mail clients or reload my OS
For these reasons, I'd prefer the e-mail address to be a simple incoming forwarder that I could manage via editing my preferences in my profile.
Edit
Mine arrived :)

Sorry about the blur. The camera on my phone has no understanding of hyperfocal distance and doesn't offer a 'manual' mode.