Bookmarks are little icons that you can leave on the Planet or Sector Maps so that you can easily be taken to the same location again. Players use Bookmarks for a variety of reasons, be it marking Allies or Enemies, or tagging res fields so they can easily locate a certain one again.
Adding bookmarks is a very simple process; clicking almost anywhere on the Planet or Sector Maps (with the exception of Suns, Wormholes or NPC fleets) will bring up an option to Bookmark that location.
Looks like i want to keep an eye on this processing complex by placing a bookmark on it. Clicking the Bookmark option will leave a little icon on it.
Now no matter what sector/planet i am in/currently looking at, if i would like to quickly look at this processing complex all i need to do is select this bookmark, and BAM; i will be looking at this processing complex again.
Once you are done placing a few bookmarks you will want to be able to access them, and you can do so from your Bookmarks Manager; you will find this in the top right hand side of your screen on both browser and mobile:
Either platform will give you the same options (at first):
From here i can see each Bookmark i have placed, as well as the specific cords for that Bookmark. If they click anywhere on the Bookmark name or icon the players screen will reload on those exact cords. Clicking the red "x" on the same line as a bookmark will remove it, though be sure you do intended to remove it as there is no confirmation asking if you are sure; once clicked that bookmark is gone. You can also edit the name and color of the Bookmark by clicking the pen option right next to the red "x".
From here you can edit the name of the bookmark, as well as change the color it appears as (default is white). The colors themselves do not change how the bookmark functions in anyway; they are just for ways to better help categorize their bookmarks. You might bookmark hostile players as "red, or friendly players as "green"; the decision is left up to the player to change the colors (or name) as they see fit.
On the computer version of VC you will also see an attackers tab in your bookmark manager.
This will show you all the players that have recently attacked your fleets or base and how many times they have attacked you. Clicking on the magnifying glass will load up the Battle Report for the most recent battle you had with them, and clicking on the target symbol will bring up the players base, just like if you had placed a bookmark on it. The skulls represent (??tracking this down??). Again, you will only find this on the computer version of VC; since you bookmarks live in the same place as your profile on Mobile there was no need for it to be added to the Bookmarks tab, as you can easily access your Feed from your profile as well.
Players are able to "Tag" npc fleets so that they can easily find this type/level of fleet again in the future. This function works very similiar o the "Find Target" feature found in the Workshop for crafting materials, and in Sector Activities. Lets say I tag a level 35 Rebel Raider fleet; this does not tag that exact fleet i clicked on, but any level 35 Rebel Raider fleets that may be spawned. I will now be able to go to my Bookmarks and go to the "Tagged" tab. From there i can see any type of fleet i have tagged, and clicking on that tag will take me to the planet or sector map where one is currently spawned. If none are currently spawned i will recieve a message stating so, asking me to check back later.