I learned (the hard way) that Battle.net does not count all of your map's hours played toward the overall total that counts for your map's place on the Top Played list.
Instead, battle.net only counts the TOP-MOST VARIANT (NOT necessarily the default, but literally the one on the top of the list) toward the map's popularity. The other variants do not raise the map's popularity at all.
I discovered this bug when I added an update to Mafia introducing the Ranked variant. On the list, Ranked happened to be on the top and Custom (the old, default mode) on the bottom. Literally overnight following the update, Mafia's popularity divebombed from #6 to #61. On the EU server, the popularity dropped from #7 to #74 in the same amount of time. This problem eluded me for a few days before I realized there was literally no explanation for the drop in popularity; people still played at about half the rate that they used to. By hours played, that would still put Mafia on the first two pages, not on page 6. So I thought for a bit and conjectured that Mafia was only counting the hours from Ranked, since not many people play Ranked compared to Custom. At the rate that people play Ranked, Mafia would indeed be around #60 if that were the only mode. I thought of a random possibility: Ranked was at the top of the list, so maybe changing the order would cause it to go back to counting Custom's hours. Turns out I was right; in a matter of hours, Mafia rocketed up to #20 and continues to climb.
For obvious reasons, this can be a huge issue for maps that have multiple variants. BattleCraft, for example, once had four variants. The topmost one was 1v1, hardly the most popular. As a result, the game's popularity was very low even though before 1.5 it was always on the first two pages. More recently, the 1v1 mode was dropped and now 2v2 is the highest, and easily the most popular. Since then, the map reached page 2.
yeah, i had quite a laugh/cry/sigh/spit when i realized that doing melee ffa 12 player maps was the best way to hide them from consumers :D
(u have 1V1 1V1V1 1V1V1V1 1V1V1V1 etc (technically i suppose that is 1 12player ffa) ; 2V2 2V2V2 2V2V2V2V2 3V3 3V3V3 3V3V3V3 etc you get the idea .. i don't even want to do the maths on how many variants that adds up to)