The Web 2.0 Mashup Matrix is now online here at ProgrammableWeb.
What is it? It's an experimental interactive grid with Web 2.0 API's along each axis and the intersecting cells correspond to the mashups made by combining each pair of APIs. As you move the cursor across the grid a box dynamically displays details about each intersection. You can go directly from the matrix to view the examples or drill-down into this site's API database. The page is updated daily. You can get more details at the matrix's About page.
There are approximately 30 mashups included now but this list should grow quickly over the next few weeks. Readers are welcome to contribute mashups and examples through this simple form.
Mashups are a very interesting piece of the Web 2.0 puzzle and in some ways the most interesting piece. I'll post more on them shortly. In the meantime here are links to a couple of recent mainstream press mashup stories: BusinessWeek's "Mix, Match and Mutate" and The Economist's "Mashing the Web".
The matrix is certainly the biggest addition to the site since launch. Given that this is a v1 release there is undoubtedly room for improvement and new ideas (some of which are listed on the matrix about page). Hopefully it's both useful and a bit fun. Feedback welcome.