If like me you made Data Editor changes in a map and not a mod (.sc2mod) and then spent a crapload of time trying to extract the data from the map (like you could in, for instance, WC3) well check this out, you can just rename the map, changing its extension to .sc2mod and then add it as a dependency to other maps as usual and your data changes will be in place. So what the heck.

You should write a little wiki article about it!

That's cool, but when you do that, you're keeping all the terrain and other data in it, so it's taking up more space than it should. If you do that, you should probably remove all the terrain, units, doodads, triggers, etc. Then use it.

Of course, this is just an assumption.