Perhaps the more interesting question is what drove Yahoo! to shell out that reported $30 million for a single app. To be sure, Summly's text-compression abilities dovetail nicely with Yahoo!'s new focus on mobile utilities. Along with Yahoo!'s $1.1 billion purchase of the blogging service Tumblr and the launch of an acclaimed new weather app, the Summly move marks a commitment to owning the tiny real estate of the smartphone screen-and serving advertising to the youthful eyeballs that tend to gravitate to mobile devices.