[gripfx]

Songkick does exactly this. Links with various music and social media accounts, then matches concerts and festivals in areas that you specify. Whenever a concert is announced by an artist I listen to in a city I have selected, I get an email with details on where and when tickets are on sale.

[conflagration]

Thanks for mentioning Songkick, I just registered there and looks like a good service overall. Reminds me of some of the last.fm functionality I was using in the past for that matter. What its still missing, is support for the functionality I described for festivals. Yes, they match festivals for you, but they don't tell you, which bands you should see there. Also they would have to update their database pretty often to i.e. work for Fusion festival, which announces the line-up only a few days prior to the festival, or to account for additions to/changes in festival line-ups.

[gripfx]

IIRC bands that you track are in bold on an events page. No predictions on who you should see though, that's probably out of their wheelhouse. I do think they have some kind of API acces to ticketing sites though because more than once the emails I get had working links to artist presale that I could use. Another app that I use is Dice. Not sure what the avaibility is outside of the UK but I have got (relevant) suggested events based on other tickets I bought from them.