web information extraction

I want to create a shop开发者_运维知识库ping search engine that shows products from many websites and I wonder how can I retrieve information about products from those sites. I am not interested in search engine part but in extracting product information from web pages in an automated manner using auto-generated templates. Does anybody knows some good algorithms for this / papers to read..

Dapper looks pretty close to what you are looking for. http://open.dapper.net/