SAP agrees to buy expense software maker Concur for $7.3B 12 years ago
At its core, it's a handy suite for submitting expense reports. There's a nice mobile app that lets you capture receipts from your cell phone camera, and a team of (presumably offshore) auditors that will catch the most glaring errors on submissions. Generally, it's more pleasant than dealing with the typical AP department.
I haven't really played with the TripIt integration or other bells AMD whistles.