Google is still one of the largest search engines for most sites, accounting for a large percentage of potential traffic; enough to make or break a business. Why is it that when this is the case, people out-source SEO in an unmanaged way?
Throwing money at the problem saying just get me to #1! Why indeed, because a few years ago this strategy generally worked.
However, we are now in 2012, and for years google have been asking us to write great content and not spam them with links in an attempt to game their system. Recent updates to their algorythm have started to ensure that this is the case, and people who previous had many low quality links have lost their authority.
If your organic search results from Google have dropped suddenly, you could have been hit by one of two updates by Google, Project Panda or Project Penguin. If this is the case, you'll have to take stock of your inbound links from other sites, and try to clean them up. It's often harder to remove and clean up links than to create them in the first place.
Start with a Google search of links to your site and look at each link carefully. Is it from a valid source? Is there any spamming (I.E. 100's of links with exactly same anchor keywords)? For example, if wanted to search all back links for this site, I use the following query:
Armed with this, you can investigate where all your links come from, and formulate a plan to remediate. My usual question is: Would you feel comfortable talking to Google about that link? If the answer is no, try to get it removed.