If an app crashes, just before exiting, it records some information about problem. The next time you launch the app, it will detect this information, and pop up a request asking you if you're okay with sending it in.
Most days, there are no crash reports at all. But on days when an app crashes, and the user sends in the crash information, I get an email. I take all of these seriously, and they do get fixed.
When you send in crash report information, all I receive is a stack trace (a software term that means it shows me where in the source code the crash happened). Your data isn't sent in, nor any identifying information. What I receive are anonymous crash reports, but this is enough information for me to find and fix the few crashes I've seen.
I want to express my appreciation to everyone who has participated. The submitted crash reports have helped me find bugs that I wouldn't have found otherwise, and helped make the apps rock solid. Thanks.