Help! - Product Marketing + Backlinking + Sales


I am a marketing expert but currently I want something direction to move my marketing and seo work one step forward. I have done some profile linking, bookmarking and commenting. 15-20 article and now I want to do the product marketing. Its easy for me to write more content and publish and get well ranked for particular keyword. What I want is to share the products in market places. And showoff products in communities to get reviews.

Please suggest some good market and product showOff places for open source shopping cart theme and module related niche.