Forrester put someone else's money where their mouth is

It slipped my attention that Forrester are saying the US corporate social software market is worth $300M and is set to increase 5-fold over the next 5 years - remaining equally split between internal & external applications.

Points of interest:
- $300 million is not a lot of money in the grand scheme of things. But given the prevalence of open-source software in this area, is it worthwhile comparing spending on web 2.0 stuff with spending on, say, ERP?
- The equal split the internal & external uses (E2.0 has been getting more noise of late but still little compared to commercial world uses).
- The lion's share of the $ is being spent on social networking software. Which comes as a bit of a surprise. With most people I talk to, it's wikis, wikis, wikis for internal experiments. I'm guessing the social networking spend is being driven by external applications & marketing budgets!?!

UPDATE: A little information may be a dangerous thing. Check out the comments section regarding what the figures actually refer to.