In 2010 the most read posts on Google Maps Mania were, in order of popularity:
Volcanic Ash Cloud Live Tracking Map
The ever popular live flight tracking Google Map Radar Virtuel in April added a layer showing the position of the Icelandic volcano ash cloud. Users were able to not only view the non-existent planes over Europe as flights were cancelled because of the cloud but see the the location of the very existent ash cloud.
Street View in 3D
On April 1st Google released the option to view Street View in 3D. Like most other commentators I thought that this was the Google Maps teams April Fool joke.
It might well have been released as an April Fool but the feature proved so popular that the feature remains. If you right click on a Street View in Google Maps you can still turn 3D mode on.
Maps of the Nashville Flood
Historic flooding took place in Nashville in May with over 13 inches of rain falling in a two day period. This post looking at a few Google Maps that showed road closures, flooding incidents and the National Weather Service's Advanced Hydrologic Prediction Service proved very popular.
Met Office Volcanic Ash Map
The UK Met Office also produced a Google Map for the ash cloud caused by the Icelandic volcano eruption. It didn't prove quite as popular as RadarVirtuel's map. Maybe the Met should start tracking planes as well as the weather.
The Horse Headed Man on Google Maps
In June a half man half horse creature was spotted in Street View in Aberdeen, Scotland. Thanks to the readers of Google Sightseeing and Street View Funny lots of other sightings of the same strange creature in Street View were also reported.