Plenty has been said about Mesh, from Robert Scoble to Joe Wilcox, Steve Gillmor, and a healthy dose of ReadWriteWeb.

But in a nutshell, from Forrester analyst Ray Wang, is the fundamental reason that Google, Salesforce.com and every other Web-pushy vendor needs to worry about Mesh.

rwjhu (3:15:19 PM): here's google's challenge: the fundamental assumption that i want to be connected and can be connected is flawed

Look, here is the deal. I love online apps because the content they help me make is easy to share with others and because I can find the most recent version of a story I'm working on in a Google doc wherever I am... assuming I'm online.

But I'm not always online, and I live in Gotham. It's even worse in, say, Gilboa, New York, where my mom lives and where I can't even get a phone signal, let alone broadband. My mom is hooked up on a dial-up, which is better than being hooked up on dialysis, but it doesn't do much for collaboration, not even on a good day.

So I know that when I visit mom for the weekend, I'm not going to get a lot of work done.

And for now at least, desktop apps are much nicer to use than Web apps. I'm not even talking about latency, which is actually worse with some desktop apps. I just mean the pleasure of working on the desktop--the, you know, richness of the feel.

But that is likely to change. The danger Microsoft has been looking in the eye is that it was losing its purchase (fancy word for relevancy) on customers for whom Web apps are getting good enough, fast enough, to overcome the rich advantage on the desktop.

And it has been getting tougher for customers to rationalize spending money for software when they could get "almost good enough" for free.

Mesh isn't a panacea by any means, but it buys Microsoft more time to get its software + service act together by giving people a Web-branch to hang onto.

And as Ray put it, the fundamental assumption that we ALWAYS WANT TO BE CONNECTED is flat-out wrong. We want it when we want it, but we want to be able to work or play even when we're not.