Here’s an interesting post on running your company on webapps.
Of course, the issues of security (who’s responsible for it? who do you call when an employee leaves?), data ownership (how can you export your precious data if you want to move to a different provider?), legality (using gmail for business is a violation of their terms of service–didn’t check the other services), and access (if your internet access is disabled, your business is too) are skipped over entirely.
On the plus side, hey, it’s easy to get started, and the ongoing maintenance is minimal! But consider the downsides outlined above before you jump in.
It is interesting to me that that broadband is enough of a utility now, if you can get it, that a business can think of putting something as crucial as their calendar on a remote website.