Cyrus has blogged about this some time ago. Here is some more information. First I get a bug opened in our defect tracking database with a title such as
Watson bucket 64043890: Crash caused by HTMLED.DLL!COmTreeElement::RemoveInvalidItems
When open the issue I see a). a callstack ending up in the code my team owns b). link to internal Watson web site with additional information
On the Web site I can retrieve list of crashes with number of hits (i.e. times the crash has been reported for a given module and the method/address within it), version of the application and the dll that was loaded and see if there are any other bugs opened on the issue.
I can also have a look if user filled a survey with probable repro steps. Often it is enough just to look at the offending code. However, if it is not clear from the code what exactly has happened, I can download a post-mortem dump,
There is also a Web site where third party developers can sign up and start getting Watson information for their applications.
So next time you see a crash, please click 'send report to Microsoft'! :-)