There's no category for Windows 8 on MS Connect, so when we found a bug in Windows 8 RTM I found the name of an MS employee working on the feature in question on the MSDN forums, then through Google found his LinkedIn profile where he luckily published his eMail address.
Microsoft should be ashamed.
It seems like the best way to file a bug these days is to create a blog post and publish it to HN, Reddit or so...
Has impacted my system multiple times since upgrading to Windows 8. Fortunately I know a work-around (eject the optical disc in the optical drive) but still -- annoying that I cannot even report it.
The bug we found is affecting a lot of Swiss customers (I admit Switzerland isn't so big) and it took a month until I got a useful reply.
Now we have a bug number and were told that the issue should be fixed "early this year" and changes would be checked in in March. Whatever that means...
At least their employees were kind enough to reply to my eMail. But this company should really improve their error reporting.