Scying on SCoD comes in two forms and they are available via your Essence.
Basic Scry[]
The basic scry only lists areas and gives a vague indication of how many players are in that area, and their rough level. The colour basically indicates in they are in your level range. Red means everyone is out of it, yellow means some characters may be in range while others will not be, green means all are within range. Within range means no more than a 7 level difference (including LA, so its ECL that is considered) with your character.
There are two options for this type of scying. Opt in and opt out. If you opt out, your character will not be included in any scry results.
Advanced Scry[]
This is opt in only, but all players are listed, and the results are listed by player rather than by area. However, until you opt in on some options, only your character name will appear in the list. Everything else will be listed as unknown.
For the moment the results are listed via message, but there are plans to convert this to a GUI box.
You can choose to share the following information publicly: Character build, location, level (and ECL), and playstyle preference. It will also display whether you are AFK or not, regardless of preferences.
Special Note[]
Both forms of scry are independent. Setting an option with one has no impact on the other.