Rather than me go into it too much, this video covers what SalesForce are doing in the SaaS space with a new Platform called Force. The blog also covers this is some detail and the press release covers it also.
They've really thought it through in terms of scalability, security and performance. It's something managed by them, my biggest question is what Enterprise companies will pick this up or will it be the SME's? WIth their reputation in CRM space and their early start in the AppExchange program. A good coverage of AppExchange is covered at the O'Reilly Network.
SalesForce have also joined the OpenSocial bandwagon and demoed at the BaseCamp webcast I mentioned in my previous post. Will be interesting to see what integration that bring in...whether they'll be happy to open up to LinkedIn or not...