Yes it was popular... The majority of business owners are not techie. They probably do not know about StackOverflow. So answering questions asked by business owners on Linkedin was a great way to make an impression. The biggest problem with with linkedin it that it's just overrun with requiters and social media experts. It's not professional anymore.

Answers evolved from a Q/A section to a just another portal for a social media expert to just refer to someone in their network. It was really annoying... The shutting down of Answers should be a warning to anyone that is trying to build credibility on a network, it can close at anytime and all your answers/reputation is gone