One particularly interesting part of the article explores how personalization complements search. Some excerpts:
Implicit Query ... analyzes the email message the user is looking at and extracts important words from the body, subject, sender, and recipient fields. These words are automatically used in a query ... and the results are shown as a side panel attached to the current message.Search helps when you know what is out there and can easily say what you want.
We thought IQ would be helpful in sparing users the effort of generating queries, and indeed it is.
But many people have also reported an unanticipated benefit of finding information, especially when they completely forgot they had anything related and would never have generated an explicit search on their own.
Personalization helps when you do not know what is out there. Personalization surfaces interesting items you did not know about and may not have found on your own.
Search is finding. Personalization is discovering.