Vanity metrics can make you feel good but are not actionable. This is why GrowthHackers does not recommend using metrics, such as downloads, page views, or hits for driving your company.
Instead, focus on metrics that indicate activation and retention. We recommend metrics like Weekly Active Users that show the behavior of real people using your product to drive growth.
Read more:
http://www.startuplessonslearned.com/2009/12/why-vanity-metrics-are-dangerous.html
http://firstround.com/review/im-sorry-but-those-are-vanity-metrics/
https://blog.hubspot.com/vanity-metrics-to-stop-measuring-and-better-alternatives