Trendpedia

Trendpedia searches blogs and presents the search results in an electro cardiogram called a trendline. From the "about" page:

Search blogs — discover who’s discussing what, where, when and how. Trendpedia finds trends in social media. You choose the topics, enter the keywords, and click “Search Trend”. Trendpedia finds the articles online that talk about your topics. Trendpedia organizes the articles in a trendline that shows the popularity of the topic over time — you can track a topic’s trendline from three months ago up to today. Trendpedia collects posts about your topic per day. Click on the trendlines to find the articles about your topic posted on the date of choice. Watch the articles appear in the tabs below, organised according to topic and date.