I agree that it is a great strategy to have both a content site and a mini site approach to online marketing.
The content site will ensure steady traffic, repeat visits and good search engine positioning.
The multiple mini sites (one for each product or service you're promoting) will pull in direct sales, and let you run other promotions like PPC and paid ezine ads.
Hope this helps
Dr.Mani
... the Ezine ANTI Marketing
http://www.EzineMarketingCenter.com/anti/