Lame_Wolf - 8:25 am on Mar 9, 2012 (gmt 0)

1. I won't use any SEO company on the adsense sites

SEO and Adsense are completely different. It's like saying that you will ask you car mechanic to do SEO.

2. The ecom site is in such a very dry niche its difficult for me to write articles around it, so I outsourced the seo to a trusted company.

hmmm. So trusted that they managed to get you penalized. :/

3. I was thinking of developing the ecom site with a forum based around helping people with problems relating to what I'm selling. But, I'm thinking that it would be difficult for me to moderate it properly in an un-biased way. Also, I've heard that forums can become a nightmare to keep control of.

You are wasting your time with Adsense on a forum. They are well known not to generate a lot of income. Plus, as you said, difficult to moderate, esp if they are going to swear a lot, or post copyrighted material.