What is a large list? What might be the problem if I store 1 million documents in a document library? Is there an improvement from WSS 3 to SharePoint Foundation?

If you want answers to the questions, take a look at a great post at the “Microsoft Enterprise Content Management (ECM) Team Blog”.

A summary to the problem:

Any time you ask for content from SharePoint, you have to specify how it’s sorted – for example, the All Documents view in SharePoint 2007 asks for the top 100 results, sorted by filename. But items aren’t sorted by filename in the SharePoint content database – so, to bring you this view, SharePoint has to gather up all these million items, sort them, and finally display the 100 ones at the top of the sorted list.

The answer:

Migrate to SharePoint 2010 quickly to use its new features which help you dealing with large lists.