It's search v's directory. The idea is you can post meta-data on an API on your own domain using a format http://www.apisjson.org/ that can then be crawled. Right now you still submit links, but it'll start crawling. So then anyone can write a search engine (the code for apis.io is open source).

With a directory like programmableweb it's useful but you need to put your data into the repository - and then remember to update it.