Instagram was an overloaded check-in app before its founders threw almost everything out.
Kevin Systrom built a location app called Burbn that let people check in, make plans, and post the odd photo, and it was going nowhere against Foursquare. With Mike Krieger he stripped it down to the one feature people actually used, photos, added filters, and relaunched in 2010. Eighteen months and no revenue later, Facebook bought the 13-person company for $1 billion.
Instagram on Brandseum