So "Who will Mashup the Mashups?" ... Another interesting presenter at the Mashup Corner of SaaS World was api-match.com.
The service - provided by Ryogoku based Metadata Inc. - is an API search engine/directory, which allows introspection of various APIs, and side-by-side comparison with other similar APIs. You can input a search term - say Real Estate or maps - and up will come a list of related APIs. Drilling down displays all the service description information that can be found about the API, and the HTML licence page is displayed in an iframe, with the responsibilities, rights and restrictions sections conveniently highlighted in colour.
After comparing APIs, you can select those you want to use in your mash up, and click a "make proposal" button to spit out a skeleton integration proposal. Very handy!
They are continually registering new APIs, and on the site you can register your API interests and get RSS feed alerting you to new entries that match your categories.
Another interesting feature is a "Wish List" where you can register the kind of functionality you'd like from an API. Developers can review this list, and create APIs they are interested in.
From an AJAX implementation perspective, the interesting thing about this site is that - apart from the automatically generated proposals - it all happens a single page (which - to be honest - is in need of some tender loving graphic design!).
There is no real business model surrounding this site yet, and there is clearly a small but ongoing cost associated with the site. But given the frantic activity in this space, and the potential to tie up all sorts of functionality, positioning yourself at the centre of a development marketplace very positive on the prospects.
Metadata Inc. do consulting on API development and Natural Language Processing, and are involved with the Business Models Association. CEO Naoyuki Nomura is a Professor at Hosei University, and presents widely on Semantic Technologies.