We've been using that logo at Hackers and Founders meetups for the last 3 years, since we're the HN meetup in Silicon Valley: http://www.hackersandfounders.com. I actually ran it passed pg a few years ago, and he didn't complain.

But, now that we're pushing 3,000 members, we really need to change the logo. We really aren't affiliated with YC in any way. And, newcomers are starting to get confused, which is bad.