Facebook will receive $1 out of every $5 spent online by 2015 according to a new study out of Russia. If Facebook continues to grow at its current rate it will double its user base to 1.2bn within 4 years.

The ramifications upon advertising revenues have not been lost on financial analysts who are projecting a massive increase in revenues, from $1.2B per year currently to $16.8B by 2015.

More importantly for marketers, such a scenario would precipitate a paradigm shift in their approach to marketing online. With 4 out of 10 people using the internet owning a Facebook account, it could usher in an era when brands exclusively focus their online efforts on campaigns that operate within the Facebook ecosystem.