Didnt know that! That is actually Quite interesting.

I was surprised that Civ V has higher traffic than Skyrim! That should tell a little something to those who think 4X are a dying genre. I wish GalCiv II had higher numbers but hey its a pretty old game and many of its hardcore fans are not counted as they probably don't have it on steam.  I bought it retail in 2006 and then bought the expensions on StarDock Central, hehe.  Thanks for sharing that.

This is Interesting but, doesn't tell the whole story...

For instance Galactic Civilizations II is at a disadvantage in those graphs being that most of the original buyers purchased the game on Impulse (GameStop) or bought retail.  This being said those that went that way won't be included in that graph as when they play the game it has no affiliation with Steam.

As example I purchased GalCiv II prior to the release of Dark Avatar from Best Buy, purchased a hard copy of Dark Avatar direct through Stardock, and Twilight through Impulse (mailed hard copy) Not in my Steam Account.

Also the other games is not 100% accurate either, however, I'd say more accurate than GalCiv II being they have active expansions (DLC) that only are available through Steam.  But in my case with Sins, is once again I purchased retail, and the expansions I do own I purchased through Impulse (GameStop) and do not have that game in Steam either.

This is not going to be the case with GalCivIII as it's only available through Steam so those numbers will be accurate.  I would imagine 2-4 times more players play GalCivII monthly than Steam shows but, only about 50% more with Sins.

Anyways that's my 2 cents... 

Do the spikes map up with big sale events in general?

MOBAs brings the worst out of gamers. But still, the Dota 2 numbers are quite... impressive.

What else is impressive is that Banished, that little city building game made by a single dude is in the Steam top 25

Yup, my copy is the original game release (expansions bought directly from Stardock) and has no Steam involvement. Hadn't played it in a couple of years until I got the email about v.3 coming out so I loaded it up and have been playing the past few weeks re-living old memories.

The Civs and Totalwars are a fair bit ahead in this genre in player base.

Pretty sure Sins has always sold more than Elemental too. 

Odd, much of the Sins community laments that its multiplayer is not as popular as it should be. For most Sins players it is a single player game.

The most I've ever seen on ICO is 500 people. While the total playing Sins at that time was probably well above 1400, even if not that means only a bit more than a third of people were even interested in playing any sort of multiplayer at all. A good chunk of these would be playing comp stomps, mod games or with friends, and they have no reason to smurf. I'd say at most 5% of the online players would actually want to smurf, and fewer actually will because hey, that costs money.

So unless those smurfers are buying 10+ copies of the game I doubt it makes a big difference in Sins sales, and it couldn't effect the player counts.

I don't think this tells the whole story. I would imagine most players play LH with steam in offline mode so the steamcharts wouldn't track that...