Starting with Internet Explorer 9, Microsoft has added the equivalent of Google Chrome Omnibar (also available in Firefox with the Omnibar Add-On), effectively removing the secondary search bar and allowing search-engine lookups to be done from the main address bar:
This is generally very handy, except for when you try to access a website by it's hostname, omitting the default DNS suffix (which is a common practice in many enterprise environments):
While previous versions of Internet Explorer would simply go ahead and open http://sharepoint, making you a happy corporate user, now it will search your default search engine for word 'sharepoint' first and then offer a kind suggestion on the bottom of the window instead:
Of course you could simply click on "Yes" and proceed to the intranet website of your choice, however this extra step can get very cumbersome if you do it a few dozen times a day. So, how to make Internet Explorer 9 handle single-word, intranet website hostnames (also referred to as host headers) in the same manner as it did in the older versions?
Simply go into the Tools menu in your Internet Explorer (the 'gear' icon on the top toolbar) and select 'Internet Options'
Once in the 'Internet Options' dialogue, go to the 'Advanced' tab and find 'Go to an intranet site for a single word entry in the Address bar', under 'Browsing':
Just make sure that it is selected/checked, then click OK and this 'feature' shall annoy you no more! Enjoy.