The internet has the potential to reach a massive international market effectively and with great speed. It is obvious why a business would want to tap into this marketplace.Looking purely at search engine marketing, there are a number of strategies and techniques which need to be implemented in order to get found in the search engine results pages (SERPs). Other than paying for advertisements (known as pay per click), a very powerful way of gaining the top spots in the organic search results on the left of the Google search results is SEO, or search engine optimisation.However, SEO is partly a theoretical science. There are some definite techniques which are well-publicised and which are approved and encouraged by the major search engines, but are kept secret because of the incredibly competitive and lucrative market. SEO experts need to constantly monitor and adjust programs to stay ahead. To show how volatile this arena can be, here are a few examples of what can happen even when you are following all of the (undocumented) rules.A year and a half ago, Google implemented a major change in the Google algorithm. This change banned all duplicated and affiliate landing pages and websites. Up until this time, marketers had been using Pay Per Click to generate some incredible incomes online. Over a period of weeks all marketers who were deemed to violate the new terms were banned… for life!Did Google care this amounted to a huge loss of revenue? No way! Google looks only at what its core purpose is: to provide its customers with the best possible search experience. This means that when their customer types in "best golf clubs”, Google wants to direct the searcher to a site that has tons of information about golf clubs. They don’t want to send the searcher to a page which says "Golf Clubs – Buy into this Get Rich Quick Scheme so YOU can earn a million dollars a month and will have all the time in the world to play golf!” Sound familiar?So the infamous Google Slap changed the marketing industry. Many marketers turned to social media and organic search marketing to replace their lost incomes, and so did the software developers and the creative entrepreneurs. They could sell automated systems to speed up the submission process, and create a huge amount of content and websites on autopilot, to effectively ‘hack’ the SERPs.But Google doesn’t miss a trick. Earlier in 2010, many SEO companies using dubious methods watched in horror as their clients suddenly plummeted off the front pages and into obscurity!Again, this was a shift in the Google algorithm installed to stop dishonest marketing of businesses. This adjustment to the system had a massive impact on marketing online; so great in fact that the change became known in SEO circles as Florida. Florida – Hurricane – get it?These are two of the major changes, but tweaks to the system happen on an almost weekly basis. The changes are not telegraphed or explained. Currently a change has been made which identifies keywords and businesses which Google has decided would benefit from a local search or Google Places result. They assume that if you would like to buy a product which can be bought in your immediate area, this is what you will be looking for – a store which is a short drive away. This is known as QDL, or query deserves local. This change has increased substantially the importance of having your business listed in Google Places for the keywords which relate to your products or services. There still seems to be a random nature to which keywords Google has identified for QDL, and this will be adjusted no doubt in the months to come.These constant sidesteps by Google show how important it is not to be complacent when it comes to marketing a business online. A search engine marketing company may have 10 years’ experience, but this means zilch if they are not up with the game. Strategies which may have worked last year, or even last month, may have no impact at all and may in fact be damaging to your online presence.The next time Google unleashes one of its infamous moves – be ready to react!