You may only get these rewards once per account. Anyone can do this, even if you're brand new to the site or even staff for that matter. Post in this thread in a spoiler (so it doesn't clog the thread up) with all of the links to the site. It can only be to sites we haven't advertise or bumped an old ad on said site.

10 sites: 10 jennies.
20 sites: 30 jennies.
30 sites: 40 jennies.
40 sites: Free custom level 3 item.
50 sites: One book from the book index
80 sites: Level up any skill voucher.
100 sites: Make any skill level 5 voucher.