Previously, I set up a very simple system for letting someone do a giveaway without creating a link between your forum account and your mailing address, but this particular giveaway either hasn't happened yet or it completely fell through (not sure), so the system was never used. In case anyone else ever wants to do a private giveaway, you can do it like this:
1. PM me with a list of all user IDs eligible to receive something in the giveaway, or an exact set of conditions which users must meet in order to be eligible (eg. "any user who joined before <x time> with merit above <y> and activity above <z>").
2. I will create a URL like
https://bitcointalk.org/giveaway.php?id=123 for you (note: 404 currently). Everyone who wants to receive something in the giveaway has to go to that URL and get a
giveaway code.
3. They send the giveaway code to you along with their mailing address, and you'll verify the code at another bitcointalk.org page. You also have to keep a list of already-used codes so that people can't reuse them. You should publish some out-of-band way of accepting codes, such as an email address or a Google Forms form: if you only accept codes via forum PM, then people have to create throwaway accounts to PM you, which is annoying. You absolutely must not send someone an item without a code, even if they PM you from an account you can see is eligible for the giveaway, since otherwise someone could
also send you their code anonymously and end up getting 2 items.
This breaks the link between recipients' forum accounts and their addresses: bitcointalk.org doesn't know the address sent to the giveaway operator, and the giveaway operator can't tell from the giveaway code which user they're talking to, only that they're eligible for the giveaway. In order to identify someone, data from both bitcointalk.org and the giveaway operator would have to be combined. Codes will be completely deleted from the bitcointalk.org server & all backups after about 6 months. Note however that the giveaway operator
will have a list of addresses, and they will know that all of those addresses belong to people on the list of eligible people, so if there are only a few dozen recipients and a few hundred eligible users, it's very far from "anonymous". (There are some more fancy things that I could've done to make the whole thing a bit better. Blind signing could be used to make it secure even if bitcointalk.org was compromised, for example. But it's a pretty niche feature, so I just wanted to whip something together quickly.)
I'm not sure that
anyone will ask to set up this sort of giveaway, but I wanted to mention the possibility. If more than a few people ask me to set these up, I'll probably make it so that anyone can set them up themselves.