The placefinder service addresses a flat namespace of places. It lets users indicate where they happen to be situated geographically by:

• identifying their location as an existing place in totem
• creating a new totem place if one doesn't exist

on the back end the placefinder's goal is to provide an authoritative list of categorized places that the user could be in. The place categories reflect our estimation of demographics and population.

Place categories:

• country
• state or colloquial-regions,
• county,
• city,
• neighborhood,
• building,

The categorization of places should be the principle facility within the placefinder service. Ultimately, these place categories provide a reliable and authoritative list of places that are nearby. The system works as follows: First, as people check into a place, a best guess is made as to which category the place belongs. In this initial state, without being sure, we leave it up to the user to confirm their place-name location. Later, as more people check in, it will become clear that a particular place is, let's say, a building and not a neighborhood. At this point in time, a user will not be presented with that place if they are a kilometer away.

As the user does a lookup of existing places, only the existing places that are possible to join should be presented. E.g. if I am standing in Florida, I should not be presented Virginia. This depends on how the places in the user's immediate vicinity are categorized.

The other facility that the placefinder provides is a fuzzy search of the namespace. As the user types a place-name, the fuzzy matcher provides a set of place-name keys that we can use to join with the output of the "placefinder relevancy" search.