As others have mentioned, "Watson" is a brandname/pillar at IBM, similar to Infosphere (anything information management), Websphere (anything middleware-y), etc. It's a bunch of simple and complex, in-house-built and bought products, some of which play together well some of which don't, some of which were pretty impressive and some of which aren't.
To play with Watson Tradeoff Analytics, you can check out the documentation or get a free account with Bluemix [2]. They used to have a subset-of-functionality demo for Raptors on Bluemix as well. It seemed nifty but not groud-breaking.
My understanding is that for the real-thing, they also used the Watson Tone/Sentiment analyzers to see if players would be culturally a good fit, i.e. get along with their team-mates, not just whether they're good on paper.
[disclosure: I work for IBM... nowhere NEAR Watson, in the plain-ol'-ERP department, but I've been curious myself to figure out what the hoopla is or isn't all about]
[1] http://www.ibm.com/smarterplanet/us/en/ibmwatson/developercl...
[2] https://console.ng.bluemix.net/catalog/services/tradeoff-ana...