I haven't looked at Yammer, but Twitter seems like it's a bit 'free form' for business. What kinds of controls over inappropriate content, frequency of use, dep

I haven't looked at Yammer, but Twitter seems like it's a bit 'free form' for business. What kinds of controls over inappropriate content, frequency of use, departmental scoping etc., is Yammer coming to the table with? Small enterprises like software companies will probably be just fine with Twitter, but the real money is most likely in large enterprises with maybe 5000+ users, and real needs to control the uses that the system is put too, control abuse and so on. For example, the abuses possible with email and the web is a nightmare for these companies.