To acquire users for IllestRhyme, a user content driven rap site I started, I ran two ads: one on Reddit and one on Facebook. The results were startling.

According to the data from Clicky, the analytics engine I use most, Reddit sent me roughly 170 visitors for a 3 day ad, purchased at $30 per day. Of those visitors, only 5 registered for the site. That gives me a conversion rate of 2.8%, at a cost of $18. I'm happy to eat the cost up front for new users as they're the lifeblood of the site, but $18 is pretty extreme.

After the Reddit ad ran its course, I created a Facebook ad with the same parameters: $30 a day, however many visitors that buys me. In the first 12 hours of the Facebook ad, I received 33 visitors, 9 of whom signed up. Now I realize it's still a bit early to call the race, but even if I get no more visitors from the Facebook ad, my cost of acquisition was $10, 55% cheaper than for the Reddit ad. If my 27% conversion rate keeps up, 170 visitors would net me 46 users, at a cost of only $1.96.

I realize this data isn't comprehensive, but it's still eye opening. Part of this can be attributed to the more focused targeting I was able to do through Facebook. Facebook let me specify that my ad only be shown to the 7 million or so users who:

1. Live in the US
2. Are 18 or older
3. like #Freestyle rap, #Hip hop music, or #Rapping

Conversely, on Reddit I was forced to choose a subreddit to advertise on (along with a small percentage of the site at large). I chose /r/hiphopheads as it's a large (by Reddit standards) and active subreddit.

Regardless of the targeting differences, I think it's safe to assume that Facebook users are at least more willing to sign up for websites than are Reddit users. Interestingly, I use the Facebook registration app for my registration form. It's not clear from the data (I'm running an A/B test now), but it appears that Facebook users are more willing to sign up if they are presented with a Facebook form to fill out. For Reddit users, who are more Internet savvy, this may actually be a deterrent.

Of course this doesn't take into account what kind of users those who registered will turn out to be. It may be the case that Facebook users are more likely to sign up for something and never use it (although the initial data indicates this isn't the case, at least categorically). Those five Reddit users may be the five most active users on IllestRhyme for the next year. For $18 a piece, they better be.