Thanks, so using napkin calculation...

(1,000,000 users) x ("well over 1% conversion", we'll call it 4% to be generous) = 40,000 customers x $4 = $160,000 in revenue.

They have 6 people in the team, so allowing modest salary of $50,000 each = $300,000.

So, they must make the bulk of thier money by Adwords (11,000,000 uniques will generate $$$) as I assume the others services offered are not generating much cash yet.

Anyway, it is still a good and sustainable model and well done to them for turning a profit, something so many big(ger) name startups have yet to do.

EDIT: $160,000 x 12 months = $1,920,000. Also, allowing conversion rate of 2% rather than generous 4% = $960,000.