I had no idea that you could send PIN messages to other Blackberries. I presume that you’re supposed to keep this stuff super secret, but I love that instead, as is your wont, you can turn these things inside out and make them social.
So I went ahead and got myself a pinppl account and now I’m promoting it.
Factory Joe 
It’s great for disaster planning, actually. If your company’s Blackberry server is down, you can still get messages out via pin messaging. Some of our divisions hand out pin lists in advance of hurricane season.