Tim's blog points to an article about creating webparts in Asp.Net 2.0.
“WebParts are only a small part of the total product, but they're exciting because they allow your users to completely customize the Web pages you've created for them. For example, let's say your Web application needs to display various kinds of company data. Instead of grabbing everything-or-nothing, you can customize what is shown and how it's accomplished. If the user doesn't care to see a list of employees on the department page, he can remove it from the Web page. The information still exists on the server, but the user doesn't have to bother with it. If he wants that list back again, later on, he can use the tools you include in your Web application to re-add it. The user can also move items around and customize the Web page in other ways.”
Read article
