I also suspect that the effectiveness of Facebook ads has a lot to do with the nature of the product/service being advertised, and the ad itself (just like any advertising).
Your comment applies your specific experience (unknown to me) as evidence for an absurdly general statement ("Facebook ads are worth it") and an ad hominem attack on the author of the article. Classy.
> Klicknation Inc, for which I am a product manager, is hiring.
>Our flagship product is Superhero City, a Facebook game. You may wonder if a Facebook game can support a whole (small) company, and my answer would be a resounding 'yes'.
So the (non-quantitative) data described by most of the posters here seems to say that there is one type of ad that does seem worthwhile of FB: those advertising FB games (e.g., Zynga, and your Klicknation games).
Of interest would be: who has found FB ads useful for non-FB-dependent products/services?
Since Greg (hi Greg!) works at Facebook, it'd be a gross breach of trust for him to reveal who Facebook's ad clients are. Zynga is a well-known example, often mentioned because they spend a ridiculous amount of cash on FB ads.