One of the headaches that social media marketers face with Facebook is that, as the network constantly expands its user base, its demographics are also ever-changing. This means that doing social media marketing on Facebook in 2011 can sometimes be quite a different enterprise than it was in 2008: the types of users out there are not the same, they use the site in different ways than before and thus the tools and techniques available to marketers today are equally ever-evolving.

That’s why I find this infographic over at Mashable (designed by JESS3) quite useful. It’s called ‘An Average Day on Facebook’ and gives a little insight into the main ways in which users currently engage with the site as well as some comparisons between stats for 2008 and 2010. It only gives a quick ‘at a glance’ type of picture (there’s simply reams and reams of data which could be looked at with 700 million users) but nonetheless could be handy for marketers trying to understand how their trade might be evolving with time on Facebook.

Take for example the average age of the Facebook user: 33 in 2008 and 38 in 2010. I would hazard a guess that it is now, at the end of 2011, higher still. This doesn’t mean that all those young users have gone and are no longer reachable on the network (they are) it just also means that Facebook is now increasingly viable for social media marketing targeting older (and typically wealthier) consumers – which somewhat contradicts the stereotypical image of social media marketing being best for 16-25 year-olds for example.

All this is important as, unsurprisingly, Facebook remains the network with the highest daily engagement (52%) when ranked with Twitter (36%), Myspace (7%) and LinkedIn (6%). Social media marketers are therefore right to devote extensive time and attention to it – that fact won’t be changing for some time at least – but the way their campaigns are constructed does however need to be constantly evolving, as the network does, if they are to maximise their potential.