Who uses WSRP to avoid vendor lock in?

I'm really curious to know how many people actually leverage WSRP to run portlets in a variety of different portals. I'm not talking about writing the portlet here and running it over there. I'm specifically interested if people are actively writing portlets within their enterprises that are then consumed by multiple vendor's portals vs. writing a portlet and deploying it locally to your portal or portals?

Don't get me wrong, I understand the commercial value of WSRP, especially when you look at service providers like financial institutions. Having control over the application and the rendered content and enabling that to be accessed in an open fashion from something other than the service provider's direct web presence is a good thing. What I'm seeking to understand is the value of the enterprise/corporate developer in doing the same thing, i.e., developing a portlet with the express intent of exposing it via WSRP instead of developing a portlet to run directly within their vended portal.

I'm sure there are plenty of "vendor neutral" responses one could make such as, "implementing WSRP for our portlet allows us to not be tied to a portal vendor." Of course, this sounds surprisingly like the main reason I hear about customers standardizing on J2EE (i.e., "developing using J2EE allows us to not be tied to an application server vendor.") I've never seen one of my customers yet switch J2EE vendors and I bet they're likely to not switch portal vendors either, hence the nature of my question.

Technorati tags: wsrp, portlet, portal