A recent post on TechCrunch gives great information on how well Search engine marketing is doing compared to other advertising methods:

“According to eMarketer, search ad spending will reach $10.4 billion this year, more than twice as much as advertisers will spend on display ads. More importantly for Google, search ads will represent 42 percent of all advertising spending, while display ads will account for just 21 percent of all online advertising.” -TechCrunch

You can read the full story here