I wrote a few months ago about the effectiveness of advertising on Facebook after some research suggested there were clear subliminal benefits to having your ad appear next to a profile of someone with the same personality traits as your product.  Which is all very nice, if a little woolly for my tastes.

Some new research by TBG Digital has an altogether more practical air to it however.  They've investigated the averge click through rate on Facebook ads and done some analysis to determine which day is most effective.  Interestingly they found that Sunday represented the best day, with a click through rate some 12% higher than on Monday, which was the worst performing day.

The Facebook ad platform uses a combination of click through rate, cost per click and cost per impression to determine how often ads are served.  In a similar way to Adwords, the better performing ads appear more frequently, so ads with a low CTR have to up their bids to get the same number of impressions.  With data showing that CTR's are higher on weekends, it might therefore be worth shifting your advertising to weekends to take advantage of the apparently higher CTR.

TBG Digital CEO Simon Mansell says the daily differences in CTR are likely related to supply and demand, as well as changes in how people use Facebook through the week. When there is more traffic on Facebook, but the same number of advertisers running ads, the frequency of ads shown per person may increase. Higher frequency general results in lower CTR.

Of course another possibility could be that people simply use Facebook differently throughout the week.  Mondays might for instance be used for catching up with what friends have been doing over the weekend or browsing their photos.  They might be doing all of this at work so have to be quick and therefore clicking on ads is the last thing on their mind.

I'm still far from convinced that Facebook advertising is worth doing, but this kind of data could help you make the most of it if you do want to try it out.  I would recommend doing your own analysis however as no two campaigns are going to be the same.