So you have to ask yourself, is “buzz” plus “free” driving educational practice and planning? Are you building a future on this premise? Are educators walking into a trap set out to attract any and all users, just so venture capitalists can make a return on investment?
Here's how this ought to work. You've got a certain group of ed-tech early adopters who are always going to be chasing the next big thing. They can't help it, and that process has been supercharged by the fact that they no longer need purchase orders or their own money to try most of the hot new things, since they're on the web and free (as in beer). No sense complaining about this, it is just the way things are and will be for the foreseeable future.
What we do need to change is the relationship between this group and, in particular, the way schools do IT.
When the early adopters find web applications that work and stick, before they flit off to the next bauble, there needs to be a hand off to the people who handle actual implementations in schools. In some cases, like GMail and Google Apps, the vendor may decide to actually address education as a market, thus allowing schools to act as a more or less conventional customers. In other cases, once a service has demonstrated some value to schools (for the sake of argument, let's say Twitter fits this definition, although that's a major stretch), what should happen is that the ed-tech geek says to the IT geek, "OK, we need to be able to do this" and the IT geek does a little Googling around and says, "Alright, let's try piloting a Laconica server." That is, the IT side insists on an open source solution to provide stability, privacy and consistency, but they actually see it as part of their job to at least try to provide such a thing.
This is as good a time as any to give an overdue shout out to Jim Klein for the work his district has been doing with elgg, which is an example of at least part of this process in action.
A lot of this comes down to not taking seriously the difference between not being forbidden from trying something and actually recommending or requiring its use to a formal grouping of teachers. If something is likely to change substantially over, say, the next three years, I don't really see the point in pushing it on teachers (well, except in extraordinary cases, like perhaps OLPC). Three years is forever on the web right now, but in schools it is an eyeblink, and it is practically an eyeblink in the education of a kid. If you have to transition from, say, one photo sharing/publishing application to another before a class of freshman makes it to graduation, you're wasting everyone's time.