Maps Spam
Users are receiving spam notifications through the Google Maps app that asks them to share their location in order to get something for free and no one knows why.
According to reports from numerous users, Android users are receiving Maps push notifications with titles such as "You Have Received a Free Prize from Google", "You Have Received a Free Prize",  "Congratulations for Winning Pixel", and more.  When users click on these notifications, they are then being asked to share their location.
For example, a Reddit post stated:
"Strange thing. Just got a push notif from my Maps app that read "You Have Received a Free Prize from Google [...]", so I figured it was some sort of Google-Play-Rewards-type thing — but once I clicked on it it appeared to be about a user named "You Have Received a Free Prize", with Maps giving me the option to share my location with them. I found the block button and that was that, but has anyone else been subject to this? What's the endgame if a gullible user decides to follow through?"

Maps Notification Spam
Maps Notification Spam
Most users who BleepingComputer spoke to regarding these notifications simply block them.
Some, though, have stated that they thought it was an ad from a nearby shop, so shared their location, but did not receive any other information after doing so. As you can imagine, this is confusing as it is not known what the location sharing is being used for.
There has been a lot of speculation as to where these notifications are coming from. Some think that criminals are using this to check when your not home in order to rob you, others that it's part of the Nearby service, or could be a way to advertise a store's products or other promotion. 
For now, if you receive a Maps push notification asking you to share your location, just block it as you never know who you are sending your location to and for what reason.
You have some theories about this Maps spam? Let us know.
Update: Shortly after posting the article, we were told that iOS users of Google Maps have also received these notifications.