Facebook groups have exploded in popularity over the past few years, with new communities forming around every kind of interest imaginable: from podcast, TV, and sports fandoms; to health support groups; cultural communities; and even chubby cats.

But it's not just Facebook users that love groups. Facebook groups are shaping up to be a powerful business tool. A growing number of businesses are creating specialized groups in order to foster online community, reach their audience on a more intimate level, and build deeper relationships with customers.

So, what's the deal with Facebook groups, and how can businesses leverage them in the right way?