There are several teams that wander to these various places to visit. Most have been chosen due to various factors, the main factor being that these locales are where, through the years, people have gathered to visit, watch, see things, etc.
The overall concept looks very interesting. Apparently there are a group of people called The Resistance whose sole aim is to debunk the game's theory/concept about these places. Each player can go to the chosen key places that are considered possible portals and visit. So if you choose to play the game it can take you all across the country. I thought it was pretty cool that the Howard home was chosen as one of the portals. And found the whole concept quite interesting, to say the least. Wiki has a whole article on the game if you're interested.