Google Trends *The power of Google's database is put to work with this tool that offers a look at trends for search terms going back several years. By entering a search term it presents a graphical representation of searches by month. Also allows for analysis by region and even cities in a region. Could be very useful for determining the location of new markets or test markets, and for identifying when sales of cyclical products may be changing.
Perfect Brainstorming *It will take a few minutes to get a feel for the information on this site but it does contain the key elements that explains a widely used idea generation research technique.
Trendwatching *Interesting site that offers a monthly newsletter examining a consumer trend that appears to be occurring somewhere in the world. Also provides access to all previously reported trends.
Wordspy *The creation of new words are often the sign of a trend and this site provides a regular updated list of new words including examples of usage. Site includes a subject index to quickly locate terms.