I came across two very interesting "portal style" web applications from PageFlakes and Netvibes. Both of these web applications are pretty slick and allow wiki style editing of pages; you can add "modules" to your pages from their respective libraries and also organize your page layout.

The approach that both PageFlakes and Netvibes has taken is very similar to what Microsoft Windows SharePoint Services Version 3.0 (aka WSSv3) and Microsoft Office SharePoint Portal Server 2007 (aka MOSS2007) provide via Web Parts. The major difference is with Web Parts you need to be in "edit mode" of a page in order to add parts or modify the layout of the page.

It is important to mention that there is a major (ok HUGE) difference between what PageFlakes and Netvibes offer as opposed to what WSSv3 and MOSS2007 provide. The simplest way to explain the difference is that WSSv3 and MOSS2007 provide a rich set of business features like document management, search, collaboration and more which you can read about in the earlier reference links. I believe the most important difference to note is WSSv3 and MOSS2007 provide a development platform for building Business Applications that integrate with a Line of Business system (LOBs) and the Microsoft Office system. 

PageFlakes and Netvibes appears to focus more on the Social Universe allowing you to build home pages that help you track blogs, RSS feeds, Skype, News, Movies and lots more.

All of the technologies are very interesting and worth a look depending on what problem you are trying to solve; business or personal.