Map developers can assign a level that their map unlocks at. Or they can simply specify that their map unlocks at level 1, in which case it will be available to anyone.

The advantage of assigning a level is your map gets increased visibility. Whenever someone levels up to that level, they will be shown your map in the level-up window. To maximize this benefit, you should try to choose a level with few other maps assigned, since the level-up window will only show 5 max.

However, this isn't easy to know unless you leveled up recently. I hope to some day make a page that shows the number of maps assigned to each level (or, even better, suggest a level when creating a map). Until then, however, I'll just post the totals right now:

 UnlockLevel | Num maps
-------------+-------
           2 |    11
           3 |    35
           4 |     7
           5 |    31
           6 |     5
           7 |     4
           8 |     7
           9 |     6
          10 |    19
          11 |     4
          12 |     7
          13 |     2
          14 |     1
          15 |    10
          16 |     4
          17 |     2
          18 |     2
          19 |     3
          20 |    14
          21 |     3
          22 |     3
          23 |     1
          24 |     2
          25 |     6
          26 |     1
          27 |     2
          28 |     1
          29 |     1
          30 |     7
          31 |     2
          32 |     5
          33 |     4
          34 |     2
          35 |     4
          36 |     0
          37 |     1
          38 |     2
          39 |     3
          40 |     2
          41 |     3
          42 |     3
          43 |     2
          44 |     3
          45 |     4
          46 |     2
          47 |     3
          48 |     2
          49 |     4
          50 |     3
          51 |     3
          52 |     1
          55 |     1

If your map is on one of the popular levels (anything with more than 4), I recommend moving it to one of the less popular levels.

The unlock level can be changed at any time, even after a map is public. Just open the map and click "Edit Name / Description"

Edited 6/20/2014 08:21:07

Wait... there are maps unlocks at levels higher than fizzer?

And how many the unlock level 1 maps? I changed my maps to level 7-13-18-24-29.

A couple of mine unlock at local deployment level (49 is it?) because they are meant for LD setting to be used.

Awesome, I didn't know I had the ability to change this.

Well, it is kind of obvious any number that's a multiple of 5 if going to be picked more often.

whats wrong with #36? :p

I made my map as level 36

I can safely say I am responsible for most of the level 3 map unlocks. Near all of my maps unlock at that level. However I do not plan to change it as I find that the system is flawed in one minor way, let me explain.

It makes sense that the better the map the higher the level it unlocks at, for me this would put my Solar System at a reasonably high level. This brings 2 problems.
1) People being stereotypical of all my maps after playing the lower level ones.
2) Less traffic overall when a map is released.

I set my big Africa map as level 37

I decided to put my maps on levels depending on the actual rating.