To quote Google Trends,
Google Trends analyzes a portion of Google web searches to compute how many searches have been done for the terms you enter, relative to the total number of searches done on Google over time. We then show you a graph with the results – our Search Volume Index graph.
Above is a graph showing a search for the two terms; genealogy (blue) and "family history" (red). It should be interesting to all genealogists that the trend is definitely downward from 2004 to the present. There has been a steady but significant decline in the searches on the Web for these terms. The drop in searches for genealogy is more significant.
Interestingly, the same downward trend appears for a search of the term "familysearch" except the number of searches is much more volatile.
The above graph shows the search term, "familysearch" but the overall trend is down.
I am puzzled as to the reason for the downward trend, but I speculate that overall traffic on the Internet is growing so rapidly and the amount of information is so immense, that genealogy is being overshadowed by other online interests. Google Trends may be a more accurate view of the real interest in genealogy, as opposed to commonly quoted statements about genealogy being the most popular or one of the most popular hobbies in the U.S. However, the explanation may be more simple, when was the last time you did a Google search for the term "genealogy?"