Google (News - Alert) updates its search algorithms over 500 times a year, and for an SEO company, that means new writing and development strategies are needed all the time to stay competitive.

In such a rapidly changing industry, it's important to stay on top of the game. Here are some of the big changes and trends for SEO companies to watch out for in 2013:

1. The Growing Importance of Social Media

Social media will play an even larger role than ever in 2013 in determining how well sites rank in Google, and this is perhaps the biggest factor that writers for an SEO-based company need to consider. A large presence on sites like Facebook (News - Alert), MySpace, Google+, LinkedIn, Twitter and others will only increase in importance over the next year, as Google heightens the importance placed on a page's popularity on these sites, particularly Google+.

2. ESA (Google Equivalency Score Algorithm)

This new algorithm, expected to launch this year, works something like Google's Adword Quality Score, where keywords are given individual quality scores based on various factors. The bid amount advertisers choose and this keyword score will be combined to achieve an ad's rank in Google. This should prove huge in leveling the playing field for business, as one possible effect of this change would be a different order for search results for the same search each time, giving smaller sites a chance to better compete with larger, traditionally much more dominant sites.

3. Individual Author Rankings

Going into 2013, Google is planning to assign bloggers an author rank based on various criteria, like domain expertise and niche experience. The rank will play a significant role in determining where an author's content ranks on Google searches. Another factor is the inclusion of a writer's Google+ profile (which will be linked to an author's published content) into the overall author rank, further complicating the system by which an author receives their ranking, and therefore, where their pages rank in Google.

4. The Link Disavow Tool

This relatively new tool, which will collect data on the backlink structure of sites, will make it more difficult to backlink from blog and forum posts, and to generally cut down on spam sites and low quality backlinks.

5. Mobile Browsing Compatability

As mobile devices and tablets become increasingly sophisticated, they’re used more commonly as browsing devices, and because of this, it is becoming increasingly important for sites to have a mobile version ready for users. The shift in traffic to mobile devices is making it very beneficial for SEO firms to build mobile versions of their sites.

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These changes will mean big things for every SEO company and individual website owner on the Internet – they’ll have to reorient their strategies, make changes to their websites, and then begin preparing for the next round of changes.

However, all are all designed to provide users with a better experience, and will ultimately help drive sales and increase website quality in every niche on the Web.