So your looking for trends. Perhaps you are doing a trend analysis. For this example, lets say you are studying organic food. First stop, Wikipedia.
And you learned a few facts about the history, its definition, and maybe you caught the un-cited fact, “since the early 1990s organic food production has had growth rates of around 20%.” Great, but this is a pretty vague trend.
Try the Google News Archive. Wow, did you see that? There is a significant spike in 1970, then again in 1990, and then steady building for the last decade. We can see the historical moments of significance, and by closer examination understand the important events at those times. Clearly, organic food has gone mainstream in recent years, at least in the news media.
So what about in the populace? Does news reflect the general vibe? Checkout, Google Trends. Unfortunately, Google Trends only goes back until 2004 when the database begins, but we can get a very close look at the contemporary picture. In this case, there are two main take aways. First, searches are flat while news is up. We can’t draw major conclusions from this, but it is counter intuitive. Second, at least among Googlers, people searching for organic are English speakers. Again, don’t take this to heart. The word organic is English, so obviously people searching for the idea will use their native term.
Putting these tools together can help you spot and understand trends really fast.