Here's a great article on stats on how Facebook mobile is dominating its competiton:

http://www.allfacebook.com/facebook-mobile-dominates-2010-10?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+allfacebook+(Facebook+Blog)

Note the stats on apps.
And it's not just about Facebook development:

Know that Copeland Casati Media offers app development to put  your business in front of and interacting with your customers in their preferred method of connecting to you.

Here's an excellent presentation by my friend David Stephenson on the smart use of social media during a disaster / terrorist event: 

If you're in government / leadership positions consider reading: