I haven't advertised on Google in over 2 years, we started in 2002 and we are getting ready to start again. In reading the forum it seems quite a bit has changed that I'm trying to understand.
My question is this - I'm an amateur and our account has 100's of keywords in groups. It seems that the right way to do it is to create more groups. If I move a keyword to a new group does it lose it's history? What is the best strategy for re-organizing the account before we unpause our ads?
The keyword won't lose its history, but if it hasn't run in over 2 years, I'd doubt that Google would use that data in its calculations. Seems "too old" and "too irrelevant" - too many things have changed since then (competition, placement of ads, user click behavior, etc.)
I wouldn't worry about losing history (and the short term negative effects it can have on CPC) at this point. I would focus on creating the most efficient and relevant structure 1st.
You'll make up any "losses" quickly by getting better QS, lower CPCs, etc with a efficient account structure.