Sharepoint makes it easy for end users to create database driven websites.

Sharepoint enterprise deployments are rapidly growing for the same reasons IE grew so fast and Google Calendar killing Kiko; Integration.

Sharepoint integrates with Outlook, Word, Active directory, IIS, SQL server, ASP.net.

An added benefit is that you host your own data, which many enterprises seem to love.

Show me a web site creation platform that integrates into the MS world like Sharepoint and I'll show you some rich founders... hint hint