We normally talk about search engine optimization (SEO) on this blog and how the changes to Google's algorithms can affect how you rank for certain keywords and keyword phrases, but another huge part of the equation comes from search engine marketing (SEM). This is when advertisers purchase ad spots on the search engine results page. Not surprisingly, we're seeing huge growth here.

According to a new report put out by eMarketer, spending on search advertising is expected to hit $19.51 billion in 2012. That's based on US spending alone and it represents a huge 27 percent growth compared to last year's figure of $15.36 billion. That's a lot of money and, not as you can likely expect, Google is leading the charge when it comes to scooping up that advertising revenue.

Part of this increase in spending is fueled by the upcoming Summer Olympic Games in London, as well as the US Presidential election, along with other major elections around the world. They're saying that Google will have a 77.9% share of that revenue for 2012, followed by Microsoft's Bing at 7%. The growth will slow over the next few years, but search ad spending will continue to rise.

And yes, Yahoo and AOL will be bringing up the rear with a combine share of barely over 5%, eroding down to even less by 2016. Google will be snatching up most of that, but Microsoft gets a small increase too. At least, that's what the predictions are saying.

What does this mean for all the SEOs in the audience? Getting higher rankings could prove even more valuable than ever before if advertisers are willing to spend that much more money for prime spots on the SERPs. Will you be shifting your focus from SEO to SEM? Or will you use some combined effort between the two?