I found it interesting that Entellium, a CRM software company, is abandoning its browser based CRM application in favor of it's rich client CRM application.
This is one of several recent events that signals (to me) that a larger "Software + Services" (S+S) inflection point is now underway.
Looking at Gen Y office workers as a leading indicator, I'm often amazed at how many actually *prefer* to use rich Windows applications. The browser is just an alternative interface, much like a mobile phone.
eMarketing is a never ending battle and compromise between "reach" vs "rich", with maximum "reach" and lowest common denominator channels winning out, so I don't see this trend significantly impacting the custom interaction front lines. A website and simple HTML emails will always be guaranteed to reach a wide audience.
But I think productivity and development tools will most certainly be revived in a S+S context. Even Salesforce.com, known primarily as a web-based application, has converted me to their S+S development model of using Eclipse (a rich Windows application) to communicate with Salesforce via webservices, and I would expect the deployment of an Adobe Air-based Salesforce application to be announced in the near future to keep them relevant with this trend.
"Multi-client" may become the new buzzword that replaces "multi-tenant" in SaaS circles.