share of wallet
The brilliant Jerry Shereshewsky at Yahoo! chimes in with another riff about the Bowling Green orchestra. "Music isn’t a centrality in their lives, although it probably once was. The orchestra can extend their relationship, increase their perceived value and get lots of word of mouth (not to mention a few bucks too) by sharing programming thoughts (aka playlists) for their greater audience. If you like this concert, here’s some other stuff you would love. Send them to an affiliate link to buy or download."
In other words, share of wallet, not share of market.