EghtesadOnline: On Cinco de Mayo, millions of Snapchat users willingly turned their selfies into an ad for Taco Bell. The app’s augmented-reality camera filter, known on the service as a Lens, let them see their heads in the shape of a giant, wobbling hardshell taco, with lettuce and tomato poking out and the fast-food chain’s logo in the corner of the shot. In the one day it was available, the filter racked up about 224 million views.