Google Trends shows you what the world is searching for. Using Google Trends you can see when searches for a particular keyword are most popular as well as the top geographic regions and cities for that keyword. You can even perform comparisons between keywords.
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Here we have a trends graph for the searches performed in the United States in 2007 for the keywords flowers, roses, and chocolate. We can see that flowers is more popular around Valentine's Day and most popular around Mother's Day. Roses, on the other hand, sees the biggest surge around Valentine's Day, and just a small bump for Mother's Day. And chocolate has jumps for Valentine's Day and Easter and then starts climbing around Halloween, peaking around Christmas. You can also look at a monthly view to see which days have the most traffic. Knowing this information can help you prepare your campaigns for the additional interest.
Happy Groundhog Day!