The Mitey Mo was a 300 baud modem designed for the Commodore 64. The Commodore 64 didn't have a standard RS-232 port so you had to either buy one designed for the user port or buy a standard modem and an RS-232 adapter. The Mitey Mo was one of several designed to connect directly to the user port.
This ad is from the February 1986 issue of Compute!'s Gazette, a magazine for Commodore 64 and other Commodore 8-bit computers. The entire text of the ad is comparing the Mitey Mo to Commodore's Automodem (by which they are referring to the Commodore 1650 though the 1660 came out in 1986). They list all the advantages of the Mitey Mo over Commodore's modem but most, if not all of these, come down to features of the software. The table in the center of the ad summarizes these features but things like programmable function keys, terminal emulation, menus, software buffer, etc. are all features of the software. I suppose the Commodore modem just didn't come with software that was as good though 3rd party telecommunications software was available.
As a side-note, this ad also lists online services that you'll get a little bit of free time for. CompuServe is there of course but the interesting one to me is PlayNet. I wasn't familiar with this service until I looked it up but it is apparently the precursor to Quantum Link (which I am familiar with). PlayNet provided custom software and an online service exclusive to Commodore 64 computers that centered around gaming. Quantum Link licensed the PlayNet software and modified it for their own use. PlayNet was only around from 1984 to 1987. However, Quantum Link became America Online and was apparently still using some parts of the original PlayNet communication protocols as late as 2005 (or perhaps later). More substantial parts of the PlayNet server software and hardware were used by AOL into the late 1990s and beyond. A D&D game that would have been very similar to AOL's Neverwinter Nights was being developed for PlayNet but was not finished before they went out of business.
I believe PlayNet only ever supported 300 baud so the Mitey Mo worked as well as any other modem for that service.
