What is the difference between General search (i.e. Google, MSN, Yahoo Search) and Shopping Search (Shopzilla, Shopping.com, Kelkoo)?

The main search engines are a well established part of our online world and crucial in the buying process. However, in reality, they are not the best consumer experience for searching for specific products. The limitation is that you only have 3 lines and a URL to sell your product. A consumer is likely to want to compare at least a couple of sites to feel they are making the most informed buying choice. This means many will click in and out, visiting a number of sites. The shopping engines allows them to search a lot more information in one place.