Well folks, it's that time of year again.
Sega is trying to take away your first amendment rights to make fun of their furry little characters.
Read the full legal notice here:
www.ytmnd.com/info/legal/sonic.pdf
I think the best part about the letter is the footer on the lawyer's email:

My legal assistant DZK has already penned up a response available here:
http://ytmndsega.ytmnsfw.com/.
I am looking into it further, in the mean time, feel free to let Sega know how much you all appreciate them shitting on their target audience.
Cheers!