Marathon tragedy shows true value of social, and Yahoo unveils new weather app

In the wake of the tragic events at the Boston Marathon on April 15, people flocked to social media sites like Twitter, Facebook and Instagram to scour their timelines and newsfeeds for real-time updates, breaking news and devastating eyewitness accounts, including images and videos of the bombings, some of which were too graphic to air on the evening news. The tragedy magnified the true power of social media, both good and bad.

Here’s that and some of the other top marketing and social media related stories that happened during the week of April 15.