First, a disclaimer: I'm not - by any stretch of the imagination - an expert in these matters. It's quite possible that I could've got better results with more time invested. But I still think this is a useful comparison because, let's face it, not many people actually do have the time needed to invest in a proper online advertising strategy. Especially if you're just a one-man-team like me!
So with that out of the way, I want to describe my experience using both Google's AdMob advertising platform and Facebook's platform for advertising War Worlds. My goal with the campaign was basically to get more signups in the game, a metric which I can measure directly by looking at the number of new signups in the backend (it's not so easy to track where the signups come from [not impossible, just not easy], so I decided ran both campaigns separately).
As I said, very unscientific, but the ad I ran on Facebook was the one on the left. The text for the ad was "A new 4X MMO for Android. Explore, Exploit, Expand, Exterminate!".
I decided to target it at people in the U.S. and Australia who "like Mobile phones, strategy games, Massively multiplayer online games, Strategy games or mobile phones."
I gave it a budget of $20 over three weeks (i.e. just over $1 per day).
AdMob
AdMob is Google's mobile ad network. You create an ad and it displays in any app which use AdMob's SDK. I used the ad on the left, and while the Facebook ad landed users on the War Worlds home page, this one landed users on the Play Store (this is a requirement of AdMob ads: I would have preferred clicks to go to the website here as well).
For this ad, I targetted only Android devices which support War Worlds (i.e. Android 2.3+). There's no fine-grained filters like Facebook ads (so I couldn't, for example, show it only to people interetested in strategy games). I set the budget to $1 per day.
Results
To my eyes, the results are conclusive: Facebook was a complete waste of money, while AdMod is making a noticeable difference in active installs.
The Facebook ad, over the course of about 3 weeks and $20, garnered a total of 61 clicks. According to the "full" report that Facebook provide, I got 94,173 impressions. That's a click-through-rate of 0.065% and cost per click around $0.24.
Looking in the game's backend, there was no bump in new signups to the game at all (really, even if every one who visited the site signed up, that's only 61 potential signups, which -- over three weeks -- is not even a blip). Even though the Facebook ad was seemingly targetted very specifically to people who were actually interested in my genre of game, the actual number of clicks and actual signups wasn't even noticeable. If I maybe had money to burn, I could double or triple the daily spend and see some results, but for a game like mine, where the budget is already pretty razor-thin, it just doesn't seem worth it.
The AdMob ad, on the other hand, for a similar per-day budget, had quite a noticeable impact. Below you can see the impressions I got over the last few days:
The impressions seem to peak while Google figures out the best number of impression to get the number of clicks I want. So the first two days were slightly above $1, but then it plateau'd and the following days all cost pretty much exactly my $1 budget. But you can see, 236 clicks over only 9 days. Click through rate is an order of magnitude higher at 0.32% and cost per click is only $0.04.
And in terms of actual results -- i.e. signups within the game -- well, I think the results speak for themselves:
The yellow line there is the number of new empires created on that day and you can see the big jump after the ad started running. The red line is "7-day active" empires (that is, users who have logged in to the game in the last 7 days) and the blue line is 1-day actives (i.e. the number of users who have logged in in the last 24 hours). You can see the obvious jump on the 11th, when the ad started running. It's only been running for 9 days now (compared to the Facebook campaigns 3 weeks), but if this trend continues, I seen no reason to stop this campaign after the three weeks.
Conclusion
The conclusion seems pretty obvious, at least for me, in my particular situation. Facebook ads do not work, and AdMod ads do work. Maybe I could have spent more time tweaking the Facebook campaign to get better results, but when "time is money", why would I spend time on that when I can spend the same time and get orders of magnitude better results with AdMob?
Update
So I've been informed that Facebook actually does support mobile-only ads. Putting in the URL to the app on the Play Store automatically triggers an "app install" mode which displays ads on mobile Facebook. I suspect this will be much more lucrative, so I'm going to give it the same $1 per day budget and give it a go for a few days. Expect a new blog post in a week or so with the results!