Surprised it hasn't had it's own thread yet! I noticed it in my list of apps whilst digging through the Metro apps list and it's a program that creates step by step instructions (though it's a tad fiddly to use). It is then exported to an MHTL file.
Instead of talking about how to access it, how about I show you? ;)
It did get a quick mention here though.
Loved this app since it appeared in Windows 7, ranked up there with Snipping tool
Yep been there in Windows 7 its pretty good!