Matt alluded to the search innovation that’s taken place at Google and Yahoo. Another example comes tonight from Yahoo, which has radically improved the searching tool for its web mail. As anyone who’s used both Gmail and Yahoo Mail knows, one of the standout features of Gmail is its search ability. But Yahoo seems to have leapfrogged Gmail’s search, for now, anyway. The Sunnyvale company has rebuilt its search capabilities, expanding its indexing to include photos and attached documents, and designing a user interface aimed at making it easy to drill down to the messages you want to find.

There are lots of little improvements to Yahoo’s mail search that make it far smarter. But especially clever are the photo and attachment views. A single mouse-click will bring to the surface all the photos in your in-box, displayed as a page of thumbnails. Ditto for document attachments.

Yahoo has also added a side panel that lets users refine search results by sender, date or other criteria.

Power users can also build more precise search queries right in the search box, such as “from:michael” (only messages from michael) or “tahoe -from:bob” (anything on “tahoe” not from “bob”)

It’s incremental innovation, but important as it helps nudge up the bar for the whole industry.

Rebuilding the search capability was a massive undertaking, Yahoo’s Drew Garcia tells us. Until today, Yahoo only indexed the subject and sender fields of an email message. Now, the company is vowing to go back and index the entirety of every stored email message and attachment in every Yahoo Mail account in the world. That’s many, many terabytes of data stored across a dozen data-centers. Because of the scope of that task, Yahoo says it will take several months to roll out the new search capabilities. Some users will see it starting tonight. Others will have to wait.