Heart you!

What's up with saying "I heart" something? What is this verb "to heart"? I imagine a conversation something like this:

Paramore are a band

Are bands plural or singular? This one really pains me because the rules have changed, which creates a bit of confusion on some parts. Usually when you have a group made up of many parts, you refer to the group as singular because the group is one entity. For example:

A flock of birds is sitting in that tree.
A box of chocolates is a really cliche Valentine's Day gift.
My collection of MST3Ks is extensive.
My family is dysfunctional.