The Wayback Machine - https://web.archive.org/all/20050203010713/http://www.travelocity.com:80/info/info_popup/0,,TRAVELOCITY:EN|TF_MULT_DATES,00.html

The +/- 1 to 3 days search option

Now you don't have to commit to specific dates on your round-trip search to compare total prices.
Here's how it works:
  1. Enter your preferred depart date and return date
  2. Pick the days of flexibility around each preferred date. If you are locked into a specific depart date or return date, choose the "exact date" option.
  3. Compare prices for all your possible trip date combinations. (Currently, this feature is available for US and Canada searches only.)
You may find that you can stay a few extra days and save money!