Having been in the search marketing and web development business for the past 10 years, I assume a numbr of things. One of them is that anyone running an e-commerce business has an understanding of where their pay-per-click ads (PPC) will display. Many merchants aren’t aware of the reach that can be achieved with a campaign at Yahoo Search Marketing or Google Adwords.
I came across a search engine comparison chart at Mikes Marketing that provides a simple layout of the relationships between the major search engines and what powers the paid listings, search results and the directory. Take a look at Mike’s Search Engine Chart.
For something more interactive, you can always take a look at the Search engine relationship chart at Bruce Clay. BruceClay.com has been a leader in search marketing for many years. They have a nice toolset for any webmaster and also offer top notch paid tools. From their chart, they provide links to details regarding each search engine and provide submission URL’s for each. 
It can be a good idea to see what other sites are doing to reach their audience and obtain top rankings. A focus on the internal (on site) methods that Bruce Clay is using should give you some insights on areas where you site might be lacking. They have always been a white hat shop and have always been at the top of the game.