So indication as to the type of data available, the format of the data (json/xml/yaml/etc.) would be really helpful as is some pricing if you have any estimates.

Yep, I thought plain examples of input and output. I'm obviously a bit nervous about pricing estimates (I might need to raise them later).

examples and pricing :)

how is this different from the echo nest? what kind of data are you extracting from wikipedia?

i'm building http://cloudplay.fm and would have a need for an API like this.

This will be more specifically 'release' or album oriented metadata than the echonest, which is far broader in scope and whose own metadata is more track oriented.

Arguably, being album oriented goes against the trend in the world of the 99p download. But there still exist niches where album orientation is important.