The "personal communicator" moniker that Sony has been using since 2006 was well suited for the original COM-1, which according to the press release was "designed for people who use instant messaging as a primary form of communication and networking for their social life." The COM-2, on the other hand, marked a shift of focus to mobile web browsing, which explains why Sony uses the "fun of a PC in your pocket" tagline in its marketing campaigns
Given the recent software update and direct video uploading to YouTube feature, the unannounced name change makes sense and is a smart move by Sony. The fact that "mylo Internet Device" could easily be shortened to "MID" isn’t lost on me either.
And since "personal communicator" doesn’t have the same mainstream appeal as "internet device," especially these days, maybe the $300 device will see a healthy boost in sales.