For those of you that do not play with the tools in the Google Labs, you may not have yet noticed the added feature to Google Trends.
Google Trends is a tool brought into the Google Labs in May of 2005 and used to see changes in trends for various search terms. For example, doing a search for [Google] on Google Trends will show a graph over time that reflects changes in trending. At some points, you may see a letter that corresponds with a news story at that point in time that may explain changes in the graph.
What I feel is one of the more interesting parts of Google Trends is the ability to see the top 100 trends for any day. Do not confuse this with search volume; trends are a representation of changes in search volume. This looks like a great tool for finding out what the population is interested in, and something that any marketer could benefit from if used correctly.