Not only do they email you about gigs you might be interested in, they provide reliable ticket buying services that I've used many times. I can't recommend them highly enough. Songkick enhances my gig going experience (they share band set times when they know them, remind you to buy tickets for upcoming gigs, etc), and I'll continue to be a loyal customer. I've definitely caught more gigs as a result of this service and had a seamless ticket buying experience with them to go along with it.
