Over the last week Google has been running a campaign encouraging people to work for free in order to help Google improve its map data. The timing of this campaign has coincided with Google's release of its Google Map Maker tool in Taiwan, Russia and Malaysia.
Google Map Maker relies on people donating their time and energy for free to help improve Google Maps. Using the tool you can add roads, railways, building outlines and other map features to Google Maps and (once moderated) they may appear on Google Maps.
Why should you work for free?
If you regularly use Google Maps then you will presumably benefit at some point from edits made by Google Map Maker contributors. By becoming a contributor yourself you will also be helping improve Google Maps for other users.
However the main beneficiaries of your free work will of course be Google. Google's massively profitable Adsense programme depends to an extent on Google's local knowledge and mapping data. So by working for free for Google you can help Google increase its profit margin.
Another argument regularly put forward by Google in support of Map Maker is that Google Maps API developers will benefit from any improvements that they make to Google Maps. That does appear to be a good argument. At least it certainly was a good argument before Google started charging developers for using the Google Maps API.
Since the introduction of charges we now have a situation where you can contribute map data to Google for free and then Google may charge you to to use that very same map data. That is why many map developers have started calling the scheme Google Mug Maker.
What You Should Do Instead
If you are interested in mapping but decide that you don't want to be a part of the Google Mug Maker scheme then you do have alternatives.
OpenStreetMap is an openly licensed map of the world, created by volunteers. Contribute your mapping time to OpenStreetMap and the data you contribute is available to you as part of its open license.
If that sounds like a better deal to you then check out the Getting Involved, Mapping Projects and Mapping Parties pages on the OpenStreetMap wiki.