MmHmm is by Phil Libin, the erstwhile founder/CEO of Evernote[1]. I stumbled on it when looking up old connections for something I'm doing now. Here is a video of Phil introducing MmHmm[2]. In my very limited and a few interaction with him, I found him to be a kind person, and was super responsive to a small guy when he was very busy, and around its peak with Evernote (2010-2011).
While waiting for MmHmm's invite, I got invited to try Around[3]. I haven't tried MmHmm but it seems to share similar features with Around. I find Around nifty while pitching prospective customers but rather too-much-ado for, say, our team meetings - face-to-face visual meetings with audio.
After a while, all the bells and whistles wares down and we want to just stay at the basics. Just my thoughts from our small team's experience.