Rugs, Carpets and Carpeting - carpeting basement

Before we carpet our basement should we fill the cracks in the concrete floor? They are about 1/4" to 3/8" inch wide (they are the tooled lines put in so the concrete can crack)
If so what type of filler should we use? was thinking of thinset.
also we want to stain a portion of the concrete where the pool table will sit and there are some of those cracks running through that area. was thinking of filling those with thinset too. but will that hold up to alot of trafic?

Under the carpet there wouldn't be a need too, unless it were going to be glued down.
Check out these 2 websites to fing the product you need for the stained part of the concrete you want.
http://www.mapei.com

http://www.Ardex.com/intro.htm