There are certainly degrees of famous. Rooster Teeth has over 8 million fans internationally, though mostly in the gaming and animation circles of the internet. To say someone isn't famous when they achieve that kind of following is pretty narrow minded.

They've worked together for quite a while. In one of Achievement Hunter's podcasty shows "Sunday Driving" Michael talked about how he won her over through sheer persistence. It helps that they're also very similar in sense of humour, I'm sure there was a debate over who would be the one to actually eat the stack…

It might surprise you. Rooster Teeth is a pretty massive internet media company and Achievement Hunter, their gaming video branch, has a fairly huge fanbase. Michael's role is an exaggerated angry person, his wife Lindsay is also a member of that group.