The Hot Trends top is compiled only from US based searches (for now …).
If you click on any of the searches (eg. fleet week), you will be presented with additional information about that particular search:
- 5 Levels of Hotness (how searched the word is): Low, Medium, Spicy, On Fire, Volcanic
- Related searches (pretty obvious)
- The top search hour for that word (Pacific Daylight Time)
- The top geo location
- News articles for the searched phrase (linked to Google News)
- Blog posts for the searched phrase (linked to Google Blog search)
- Web results for the searched phrase (linked to Google search)
There is a Google Hot Trends Group if you want to participate.
More info at the Google Blog.