This came from the PC Gamer review of Mass Effect 2 (just some highlight of the review I found on the internet, not the actual review :)
"The charm and intimidation skills that unlocked special conversation options in the first game have been melded into the Paragon/Renegade system, which now unlocks options based on how much of a swell guy or jerk you've been."
Sounds VERY cool. I think Bioware was spying on us here :)
Also, the bad part... :(
"The way Paragon and Renegade points are handed out could have been better, however. Often you're dealing with an issue so ambiguous that either path could be seen as good or bad, and when I'm trying to be a good guy it awards me Renegade points without telling me what it was that I did to earn them."