I've given it thought in the past, and no matter who it is or what site, I always seem to end up reading it in my own voice. That said, strangely, when I read things people have written on Facebook, I hear it in their voice if I've heard them speak so I know their voice, (rkbdgurl, if you're reading this, I hear your posts in your voice even though I know how you sound. )
Oh and I forgot to mention. Certain things written by certain celebrities online or in books I read in their voice. And whenever I see "Good news everyone!" I read it in a Farnsworth voice (obviously).
Everyone who I see post enough has their own voice:
MMB7: Ted Koppel parody by Dana Carvey
Cipher: Chester the dog from the looney tunes cartoons
Jib: Progressive Flo
www: Shaggy from scoobydoo
SSSS: Margaret Thatcher
Lawdog: John Forsythe as heard through the speaker on Charlie's Angels
Dog037: Adam West
STM: Edward G. Robinson
Studdz: Sam the Eagle
Once again people forget to add me to their list.
"Fortunately the forums ping my cell phone when there is an opportunity to discuss Witts junk."-DocSocaelicus