The storefront windows of tech-savvy businesses may be getting rather crowded before long. Perhaps following the example set by "People love us on Yelp" stickers and "We're a favorite place on Google" decals, Facebook's begun to send out promotional stickers of its own. The Museum of Making Music recently received one such sticker, which you can see below, and accompanying it was a letter from Tim Kendall, Facebook's director of product marketing. Kendall wrote ,