Ranking fluctuations are an integral part of Google’s algorithm and are expected, to a certain extent. Depending on the competitiveness of a given keyword or niche, ranking updates can take place hourly, daily, weekly or even monthly. Ranking fluctuations in search results are usually caused by one or more of the following factors:

1. Changes in the number of inbound links pointing to a ranking page. The higher the number of acquired or lost links, the more likely that ranking changes will take place.

2. Changes in the content of a ranking page that affect its relevancy towards one or more keywords.

3. Technical obstacles that affect the way search engines come across a given page.

4. Search engine updates. These can be official or unofficial but when they get rolled out rankings can fluctuate significantly, progressively or rapidly, for a period that can vary from a few days up to 2-3 weeks.

Distinguishing between a search engine and all other factors can often be tricky. Google sometimes officially announces some of the major algorithmic updates on its own blogs as they did with the first releases of Panda andPenguin. Sometimes other significant updates may be unofficially announced by Matt Cutts, Google’s Head of Webspam, on his blog or Twitter account. For instance, Matt announced the much anticipated Penguin 2.0 update on his blog. However, most updates do not get announced at all and this is when things become tricky as often it isn’t immediately obvious whether ranking drops or gains can be attributed to certain on-site (e.g. updated content, technical obstacles) , off-site (e.g. successful PR activity) or technical factors as they may have been a consequence of a global Google update that was not announced. NB. Google revealed that in 2010 they made 516 enhancements to their algorithm, out of which only a handful were publicly communicated.

There are some useful services and tools that can help you work out whether an algorithmic update may have taken place:

• Mozcast – This is the most sophisticated service that reports Google volatility over the last 30,60 and 90 days based on a set of 1,000 monitored keywords. It also reports on domain diversity, the influence of Exact Match and Partial Match domains and more.

• SERPMetrics – Reports Google, Bing and Yahoo volatility on US sites during the last 30 days.

• Advanced Web Ranking – Reports Google SERPs volatility for US, UK and DE based on a dataset of 10K keywords across various verticals.

• SERPs.com – Reports Google and Bing volatility during the last 30 and 90 days based on 1,000 monitored US sites.

• Algoroo – Algoroo data relies on fluctuations in rankings of tens of thousands of organic positions primarily from Google.com.au and a fraction from Google.com.

• Kliqr Monitor. Reports Google ranking fluctuations on Google.nl and Google.be by closely monitoring 500 keywords over 120 Dutch websites.

• Local Weather – Focused on keywords with local intent. Ideal for Local SEO ranking fluctuations as it will pick up significant changes in Google Places/Google Maps/Places.