In July 2010, Foursquare had just 2 million users performing 1 million check-ins per day. By the end of the
year, that number had risen to 5 million users performing 2 million check-ins per day. "Impressive growth, yet this means check-ins per user declined from 0.5 per person to 0.4," ReadWriteWeb adds.
"It also suggests that many of those 5 million users aren't active." That combined with the less than stellar performance of Facebook Places leads ReadWriteWeb to conclude that the whole business of 'check ins' at best limited, and at worst a total fad. "In 2011 check-ins are going to go the way of the eight-track tape and disappear."