Search engine optimization. We have all heard of it, and all brands and retailers know the value of the coveted top spot on the search engine God we know as Google. 

Google wants to give its users the most relevant, user-friendly information they are looking for every time they type a search. So it developed an algorithm to quickly assess the quality of pages on the Internet, including your Web site, and then rank the best content first.

And so, the premise of search engine optimization (SEO) is simple ? make sure your Web site has what Google is looking for and steadily climb to the #1 spot on search results. Easy, right? 

Unfortunately, no. 

Google never says outright what it is looking for, and the formula is always changing.

Take, for instance, two major changes in SEO history. 

In 2011, the Panda update prevented using duplicate, low-quality content and keyword stuffing to rank higher. 

Then, a year later, Google?s Penguin update penalized sites that bought links to artificially inflate their score. 

Now another change is coming to SEO as we know it. 

This time, it is all about mobile. 

Google?s updates have all revolved around one thing: user experience. That is why this latest change comes as no surprise. 

Massive increase in mobile Internet use is changing the Internet and SEO in a big way. 

This is not just a trend ? smartphones and tablets are taking over Internet searches. 

Per comScore, more than 80 percent of users used their smartphone to browse the Internet in 2014, and that number keeps growing.

With more people relying on mobile devices to find information online, businesses and Google alike are recognizing the importance of mobile-friendly Web content. 

This new algorithm change, which we are calling the Chameleon update, is just one more reason why you need a mobile presence online.

Beginning April 21, Google will begin favoring Web sites that offer great mobile experiences, and demoting those that do not. 

Internet users, like your customers, have a better opinion of a brand that offers quality mobile Internet experience, according to Latitude. But it is more than just attitude.

Without a quality experience, mobile users are less likely to visit more than one page of your Web site, less likely to purchase a product from your Web site, and less likely to return again in the future. 

And starting in April, they will also be less likely to find your site on search engines. 

With more traffic coming from mobile devices, such as an iPhone, smartphone or tablet, Web sites need to accommodate them. That is the goal behind responsive Web site design. 

Responsive Web sites work the same across all devices, from a PC/Mac to a laptop to an iPad to an iPhone. 

Responsive design automatically adjusts Web site content based on screen size, so that users can easily navigate content, click buttons and find the information for which they are looking.

In short, it offers the best possible user experience, from a two-inch phone screen to a 27-inch desktop monitor.

For instance, do users need to zoom in to see your content? If so, Google will ding your rankings. 

What about your clickable links? Are they too close together to tell which links your thumb will hit? You will get marked down for that, too.

These are just two of the factors that Google will consider. 

Even though your Web site may show up on a smartphone, if it is not user-friendly, it could hurt your ranking.

Bottom line, Google is constantly evolving to meet the needs of its users. That means SEO practices need to evolve as well. 

Whether it means updating your current site or getting a brand new responsive design from a reliable marketing company, you need a mobile-friendly Web site. 

As marketers, you need to give your customers what they want: quality information, easy-to-navigate design and on-the-go access.

Now ask yourself, will your Web site survive Google?s Chameleon Update?