You can use Google and Twitter to track the most popular topics on the Internet. Google has a variety of free products you can use to see whether a topic is sought for or not.

For example Google Zeitgeist and Google Trends allow Web administrators and Webmasters to find trending topics their users may be looking for.

Another new tool you can use to see what people are talking about is Twitter. Twitter tracks trending topics, updated in real-time and you can even view what people are talking about in different countries and cities using the Trendsmap.