Just a heads-up in case you missed my tweet:
Marti Hearst (Berkeley professor and hands down brilliant in search research) has made her new book “Search User Interfaces” freely available to everyone. You can buy the book if you fancy having a dead-tree copy or you can read the online one for free.
I highly recommend it. You’ll learn a bout a lot of things I discuss here such as query reformulation, personalisation, query specification and a lot of other things that concern search interfaces.
Enjoy it and report back with any thoughts or comments you have about that, it’s a really exciting area of search and doesn’t get enough coverage.