One product per site or multiple products per site?

What do you think is a better strategy:
1 web site/page with only one PPC or PPA per site or multiple PPC/PPA on a larger site?

My niche is offers that would help businesses grow with products, strategies and/or financing.

Currently offering multiple offers but having low conversion. This may be to my blundering with SEO add lack of SEO?

Do you think just having one site with say Ring Central would be a better way to go? Then splitting other offers to their own web sites.

Thinking of adding my own forum to attract visitors or is it a waste of time?

Thanks!

Also reading SEO Secrets - How to master SEO techniques

Anyone recommend a similar book but more along the lines of SEO for Affiliate Merketing?

Thanks again!