This goes square up against SAP, and Microsoft Dynamics. Its going to get interesting - enterprise application suites - on the web or otherwise, are an entirely different market than monetizing eyeballs on content (ad revenue). While I am impressed with Google on many fronts, this one is definitely going to wake the Redmond giant from its sleep. Massive applications is a space that MSFT eventually gets right, and I expect they will be a very formidable force in this area.

The question is, how do you purchase your enterprise infrastructure?
Traditional C level initiative - SAP wins
RollOver momentum from OS and office - MSFT
Organic (sometimes exponential) migration web service at a time - Google-Oracle-SalesForce?

And how will those decisions be made in the future?

Why did ACT! and Goldmine let SalesForce Happen?
Cause corporations are slow to change direction. It will take MSFT a long time to turn in this direction.

But Woe to SAP when they do. It appears thats the direction (Dynamics) they are headed.

Leaves space for the services approach from Google....