I was out of town and could not attend the SDForum SAM SIG meeting on the Salesforce.com architecture, which was a shame as it seems to have been a fascinating presentation. I have been following Salesforce.com for some time. We had them present to the SDForum Business Intelligence SIG in 2002. In 2006, Ken Rudin an early Salesforce.com employee gave an interesting presentation on his experience to the SDForum SaaS SIG.
On the one hand Salesforce.com has built the first really successful Software as a Service (SaaS) application and continue to grow the company year after year. On the other hand there is a certain amount of hype surrounding the company. Here is the unvarnished story of what they do. In the USA, there are tens of thousands of companies with distributed sales forces. Each company has to keep in contact and track what its salespeople are doing, where each salesperson works out of their home or an anonymous office suite far from headquarters. Salesforce.com provides the application to manage a distributed sales force. It is as simple as that.
Salesforce.com is the perfect web based SaaS application. There is a large client base. Each client's problem is to keep contact with a distributed sales force, dictating a web enabled application. There are many small clients who do not have the resources to implement their own sales force management application. In practice each client needs the same basic functions in their application, with some minor variations.
Salesforce.com started out by offering their application to the smaller clients who needed a few seats and would have the most difficulty in implementing their own stand alone software application. With experience they made their application economic to medium sized clients with hundreds of seats. Eventually they got to the point where they could effectively support the largest clients like Merrill Lynch with 25000 seats.