I think that bookmarking is really good if you know how to get it ranked high but email definetly gets the product info to the customers. I feel like emails still are the way to go to make money with clickbank but what do you think? Do you there is something better (besides ppc).
I know this post seems like a shameful ad but have a curiosity about this. It really comes down to whether you think your emails will get tossed in the trash or if the booking doesn't get that many hits. Stuff like bum marketing really gets you like $100-$300 a week tops while the right formula for digg stuff can get tons of traffic and sales but only when you hit the top pages.
Both email marketing and social bookmarking are different ways of promoting your affiliate links. If you post useful information to your subscribers and not send any spam, your emails will not be tossed to the trash. Same case with social bookmarking.
email is the better way of promoting a thing , but the email should be very specific and informative, otherwise the place it will get in trash only.