Those buying guns from licensed stores and vendors are required to face a background check, but some purchasers buying guns from private sales at firearms shows and online do not need to do so, an exception often referred to as the gun-show loop-hole.

BBC: Giffords implores Congress for gun control

Lawrence decided to attack from the east instead, coming at the city from the unprotected desert, and to do that he led his men on an audacious, six-hundred-mile loop up from the Hejaz, north into the Syrian desert, and then back down toward Aqaba.

NEWYORKER: How David Beats Goliath

If Foursquare can subtly create brand associations and social media product placement in a non-obtrusive way, it may stand a chance, but to do so requires an OODA loop running at a much faster pace with a more diverse view of the marketplace.

FORBES: Is Foursquare's Bubble About To Burst?