User Bases, Pricing, Revenue, and the Value of Users
blogs.xobni.com
blogs.xobni.com
Move that down to $100K - $300K and things look a little nicer for a new startup.
Not that $1M/month is not a great looking goal, but in the traditional world that would be a pretty established small business.
Regarding Salesforce.com in particular, looks like its 2006 profit margin was 9%, but 2007's was 0.1%. The street is still optimistic though, because the company's revenues increased 60%.
For such companies, the P/S ratio is generally a more reliable metric to compare with. Salesforce.com's P/S ratio is 8.8. For reference, Google's is 13.