Currently, conversions in AdWords are attributed to the last ad clicked before the conversion happened. However, it's likely that customers perform multiple searches prior to finally converting. These reports provide data on how "upper-funnel" keywords behave on the conversion path prior to the last ad click. These funnels are not to be confused with funnels in Google Analytics, which are on-site funnels. These are the paths users take when seeing and clicking on your ads after doing a search on google.com, on the way to converting. They look back 30 days prior to the conversion. In addition to a Top Conversions report, Search Funnels consists of 7 reports including Assisted Conversions, First and Last ClickAnalysis, Time Lag, and Path Length. Take a look at this video giving an overview of the new reports, and at the AdWords blog post to learn more.