According to the Herald Sun around 400,000 Facebook users in Australia have drifted away since December 2012. The initial interest has declined, and people are tending to shy away from it. It is hard to predict whether this trend will continue, and whether Facebook will respond in anyway to try to entice users to stay. The recent increase in advertising has certainly deterred people from using Facebook, and I am sure Facebook will be aware of the correlation.
Facebook fatigue is world wide, and in fact has been much stronger across the USA and Europe. Australia is now showing the same trend, with increasing numbers dropping away. This can have a huge impact on marketing, especially on those that have invested a lot in setting up a client base. Those business sites who rely entirely on Facebook for sales, could be in trouble. Those businesses that were using Facebook to promote their website, will need to ensure they have other marketing options.
At this stage, it appears that other Social Media sites are holding steady, but this could well change. The thing to remember is to not have all your eggs in the same basket. If you have a business, make sure you use a range of methods for promoting and selling your products or services.