This seems to be just searching the clip title. For example, if you search 'curry 3' ('curry three' returns nothing), it'll return things like "Curry 2' Finger Roll Layup (6 PTS) (Iguodala 3 AST)" or "Curry REBOUND (Off:0 Def:3)". If it could match the search query with play-by-play data, now THAT'd be cool.
The NBA may be the only US pro sports league that actually doesn't mind having highlights compiled and shared online. In fact, the current commissioner has said, "We’re incredibly protective of our live game rights, but for the most part highlights are marketing."[0]
[0]http://www.si.com/nba/2015/03/01/mit-sloan-sports-analytics-... (number 30)
I think Disney has plenty enough in-house talent and they're usually pretty forward thinking, it's surprising they haven't done something along these lines.
When I took the job, the realities of licensing footage hot hard: the leagues were not keen on letting a third party like ESPN have historical, searchable footage like this available on demand. The leagues were still figuring not how to make money from digital and rights to their games are the biggest asset they have.
Things have changed since then but the tl; dr is that from 2002-2005 the reason this wasn't built by ESPN was not technical or due to a lack of imagination, but a business reason - it was prohibitively expensive / impossible to get licensing rights from the leagues.
We source our content from social media, not from the league's sites so we do not have every play but we have a lot. Usually 30 or more per game.
If you're a sports fans try it out would love to hear your feedback!