When a site matures and reaches a point of saturation sometimes very little can be done to increase natural search exposure. Adding new content simply increases keyword competition amongst your own internal pages and it serves to further bury older content.

Under the scenario above it may be a viable option to create a new web property based on a sub section of the main site with a focus on a narrower aspect of the main topic. In doing so however, if the main site sells product, is it acceptable (to search engines etc) to direct people who want to buy products towards the main site?

I'm not interested in the SEO impact per say. The "buy now" or "more info" type links would lead to the main site but would all have nofollow added. I'm more concerned with the search engine's take on this type of setup, would the satelite site get tossed from serps for being a type of "feeder" site? Even with very useful top quality content and features? Since the purpose of them would be to direct buyers to major site A from smaller sites B, C, D etc I'm wondering if they would be looked upon as "manipulating search results" etc BECAUSE they share the same owner(s). Major search engines don't seem to allow multiple sites from any one entity to dominate page one results.

Any thoughts welcome.