BL Ochman notes that the new Google Trends service does not include blogs in its calculations. After seeing the chart Dave Winer created in Google Trends comparing the terms rss, blogs, and podcasting, I decided to see what would happen if I plugged the same key words into the Blog Pulse trend service that performs the same function but only looks at blogs. The difference between what keywords exist on web pages and what people are talking about was pretty clear. First, the Google Trends chart:

Now, the BlogPulse chart:

Podcasting gets the least attention in both, but bloggers are talking about blogs while there are more references to RSS on web pages. When using these tools to study trends, be sure to use the tool that answers your question, since they’re not all looking at the same things.