Is there someplace where people can thank anonymous gift-givers without thanking them directly? Because someone just sent me an item worth 600,000sP to sell, and I'm really thankful for that because I didn't have any backgrounds yet!

There's a thread in Gift Bragging. No way to know if they'll see your message, but it's a space to thank your gifter anyway. c:

Thank your anonymous gifter here! (v.3)

: Thanks for the link! I'll be sure to go post a thank you there! :)