Bookmarking is one of the feature that I like in this game. It is an easy way to go back to the coordinates od interest, for example if you have not finished gathering or to attack inactive players for resources.
When you click on a coordinate, you will see a blank star on top right of the info bubble.
Just click the blank star to bookmark and it will shine now hehe...
When you want to go back to that coordinate, just click the Bookmark icon.
When the Bookmark menu opens, you can see the coordinates saved and what you can do with them. Just pick your actions.
If you click Go To, you will be brought straight to it. I just luv it. Veru nifty to cpme back and finish gathering so that the tile will refresh.