Fascinating. Using Missed Connections as a platform to set a context. It could be fictitious, but it's more than achieved its goal for everyone but the intended recipient.
You're right about Missed Connections as context. This wouldn't have half the impact if it was in a literary journal. Just placing it in MC makes the reader more susceptible to experiencing it as real.
Craigslist is a site where people can post classified ads for free in their local geographical area (e.g. city/metro area), similar to the old classified section of a newspaper. It also has a personals section. Part of the personals section is a "missed connections" area where people can post about an experience they had with someone where it felt like they should have exchanged contact information and kept in touch but missed the opportunity. If the other party of the missed connection happens to feel strongly and has the same idea to go to the missed connections area for the local craigslist site and if they happen to see the post from the other person they would recognize the description of their encounter and have the chance to get in touch.