I've been using Plot Projects in my Android app for about a year now. It's a really neat plugin that I would like to share with all of you.
In their dashboard you can easily add locations and notifications for those locations. Just their analytics and heatmaps by itself was reason enough for me to use this plugin in my app. Their analytics and heatmaps gave me insights of when and where my users use my app. In my case I could clearly see certain train stations having a high density of my users. Currently I'm exploring opportunities using PlotProjects to monetize my app by earning money by sending discount coupons for coffee and food retailers on these stations.
Great tool I can recommend to anyone here for new ways to improve app retention and monetization