some interesting new additions here...

[Pop Not Soda]

What are those orange and green bars in the user header?

And, what's the difference between thanking someone for their post and giving them positive rep? Is one better than the other?

Nobody touch me... apparently, I'm ice cool! I'll freeze all your asses...

[Semeraz]

Not sure what the bars mean, but mine are all over the place.

[goldenshower]

They are the vbexperience bars related to how active people are on the forum. More stuff you do here, more experience and points you have. Points tie into pet settings & other addons, some forums have RPG-style battle systems and other fun stuff incorporated to use them. Orange is points and level that puts you on, green is activity that varies by how often you come and how much you interact while here.

Thanks are faster to give and display for everyone to see totals easier, instead of the green reputation bar & comments that go to your rep. page.