Most of the comments received on my post concerning Google Trends were attempts to explain the apparent decline in Web searches about genealogical subjects. Some people attributed the decline in Web searches for the term "genealogy" to a more sophisticated genealogical community. However, many of the comments showed a lack of understanding of what Google Trends is showing.
Google records every search made by every person on the Google search engine. Here is the explanation from Google about how Trends operates:
Google Trends analyzes a portion of Google web searches to compute how many searches have been done for the terms you've entered, relative to the total number of searches done on Google over time. This analysis indicates the likelihood of a random user to search for a particular search term from a certain location at a certain time. Keep in mind that Trends designates a certain threshold of traffic for search terms, so that those with low volume won't appear. Our system also eliminates repeated queries from a single user over a short period of time, so that the level of interest isn't artificially impacted by these type of queries.
Say you've entered the search term tea, setting your location parameter to Scotland, and your time parameter to March 2007. In order to calculate the popularity of this term among users in Scotland in March of 2007, Trends examines a percentage of all searches for tea within the same time and location parameters. The results are then shown on a graph, plotted on a scale from 0 to 100. The same information is also displayed graphically by the geographic heat map.One commentator suggested that genealogists had become more specific, that is, they were searching for "Smith genealogy" rather than just for genealogy. This quote from Google answers that suggestion in part:
Does a downward line indicate lower search volume?
No. A downward trending line doesn't necessarily mean that the absolute traffic for a search term is decreasing - only that its popularity (or query share) is decreasing. Query share can be understood as the ratio between the number of queries for that term and the total number of queries (at a given time and location). Read more about how the data is normalized.
Let's take an example: suppose the city of Melbourne, Australia, has 1000 internet users and 500 of them (or 50% of internet users in Melbourne) searched for the term spring festival in October. In November, 500 more internet users moved to Melbourne, but none of them knew about the spring festival, so no one out of that group searched for that term.So the downward trend does not indicate that any genealogists quit searching for the term, it means that as a percentage of the entire network, interest in that particular term decreased. So my question is valid, is there a decrease in interest in genealogy on the Web? The answer is yes as a percentage of the overall use of the Web, genealogy as a search term has decreased.
So even though there was a total of 1500 internet users in Melbourne, only 500 total (or 33% of the total number of internet users) searched for spring festival; although although the search volume for that term remained the same, its popularity actually decreased percentage-wise.