Random setting detail: As an unforeseen consequence of developing computer technology, the Internet spontaneously became connected to the Internets of alternate Earths. For a decade, people were confused by the increasing appearance of ghost-users and their sites, who exist for all intents and purposes online, but couldn't seem to be found in person. People who were in the same place but didn't see each other were both visible on GPS tags, et cetera, and some people even ended up in live Skype conversations to prove they're really there, and indeed observed many of the same events happening at the exact same time in their video feeds. Science began to catch on to what was happening in the mid-2010's, leading to breakthroughs in theoretical physics. In the 2020's, people were generally savvy to this fact and hardware became able to identify communications from worlds differentiated enough to interfere with offline interaction (in most cases, nearby worlds are similar enough that people you communicate with will be doing exactly the same thing on both sides, and thus successfully meet with no discrepancies. Technically, even in the 90's every online communication you had was across worlds in this manner, albeit to ones so close that finding any difference is impossible). It wasn't until the 2030's that the communications extended to far enough worlds for there to be significant differences on a large scale, but these were almost always a matter of post-millennial pop culture. This decade's culture is defined by the adaptation of para-retro fashions and entertainment.