Combined advertising and promotional spending will hit $38 billion by 2015, roughly 440% more than the $7 billion projected for 2010, according to a new white paper from Borrell Associates.

In 2011, social network ad spending will grow 200%, from $2 billion to $6 billion, putting it on close to an even keel with promotional spending. Ad spending will remain close to promotional spending in 2012, rising almost 17% to $7 billion.