Don't want to revive a dead thread, but I've kind of been trying to figure out the same thing. I went through the process, put my bitcointalk ID into the site, put the signature and everything of course.
I did receive a very small amount of DeepOnion (like .01) after I signed up and everything, but nothing since it would seem. As I also understand, you need to be active on BitcoinTalk, but I am, and that's all I've seen so far.
I'm going to just head over to their forum and see what I'm missing.

the 0,01 DO is just to verify that your airdrop address was submitted correctly. Also, you will have to be active in the DO forums as well. If you don't receive any airdrop by the end of the week, simply comment on the weekly airdrop post and let the devs know that you didn't receive any DO's