Some of the most popular keywords from 2008 Year-End Google Zeitgeist include:

# facebook
# iphone
# youtube
# google maps
# wiki
# games
# google
# weather
# free movies
# lyrics
# map
# mp3
# videos
# jobs
# news
# how to (draw, kiss, write, cook, tie, hack, run, cite, paint, spell)
# what is (love, life, java, sap, rss, scientology, autism, lupus, 3g, art)
# diy (wedding, tv, solar, tile, audio, home, halloween, electric, concrete, car)

In google's own words on how the search report was put together:

In compiling the 2008 Year-End Zeitgeist, our search team studied the aggregation of billions of search queries people typed in to the Google search box. Except where noted, all of these search terms are most popular for 2008.

[tags]search, keywords, google, report, Zeitgeist[/tags]