Geolocation
In 2013, some researchers found that the Tinder app was flawed. It gave potential stalkers access to the exact location of a user for about 165 days. The company has since addressed this vulnerability.
Peo
Some athletes in New York recently discovered this to their detriment when they posted photos online. These photos were taken in a club and showed them wearing expensive watches. Some enterprising female criminals noted the geolocation, made friends with the athletes and stole the items later from their hotels and homes.
Catfishing
Many lonely women have been conned by men they have met online, parting with significant amounts of money. A good-looking, respectable man may strike up a friendship online and eventually start requesting money because he must undergo surgery, is trapped in a foreign country, has lost a limb in an accident and so on.