danimalSK - 11:21 am on Jan 31, 2012 (gmt 0)
My take on it is initially they'll use this data to make Google+ and YouTube more attractive to the music industry. Nearly all of the top "brands" on Facebook (and Twitter) are musicians / bands, if they can persuade some of these onto Google+ (and YouTube) it will really help drive the consumer adoption of these products, and provide them with a semi-lucrative source of monetisation in the future.
The other spin on this is mobile payments and NFC. This is going to be a huge business in the future, and tickets will be a sizable chunk of it. Google might be gathering this data as part of a move into the mobile ticketing space.