I would think that there is a fairly even split. Who you are more likely to encounter depends mostly on the demographic of the websites you are visiting. Of the two websites I use most outside of TBT, one draws a significantly older audience (I'll be 30 next year and still seen as one of 'the kids') and the other draws a devoutly religious crowd so they both have a much higher number of right-wing than left-wing users.Sometimes I wonder, "what type of person uses the internet more: leftists or right-wingers?"
I think it's probably the first group of people. At least, that's who I usually always see on all the websites that I have an account on (for whatever reason).
Ultimately, I don't care what somebody's political affiliation is, just as long as they're not acting like insufferable/intolerable ***** trying to force their beliefs/opinions on me.