We were early adopters of the API, and we still use it to demo integration of Splunk with 3rd party dashboards.
The beauty of the API is that it allows you to display relatively arbitrary data in very compelling ways.
For example, we have access to quite a bit of data at Splunk, from Twitter, server logs, etc. A lot of our customers ask us how they can use the data that is inside Splunk and present it in a 3rd-party dashboard, so we built a demo with Leftronic.
They should market this towards manufacturing companies...
Or I could see it doing really well in high performance computing... Setup a dashboard to monitor compute clusters...
I really need to play with this!