In Google Chrome you can now hit Ctrl+Shift+N and have an anonymous
(or semi-anonymous) browser session.

details below and at http://www.mahalo.com/google-chrome-incognito-mode

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Explore Google Chrome features: Incognito mode (private browsing)Print
For times when you want to browse in stealth mode, for example, to
plan surprises like gifts or birthdays, Google Chrome offers the
incognito browsing mode.

Webpages that you open and files downloaded while you are incognito
aren’t recorded in your browsing and download histories.
All new cookies are deleted after you close the incognito window.
Changes made to your Google Chrome bookmarks and general settings
while in incognito mode are always saved.

Turn on incognito mode

Windows keyboard shortcut: Ctrl+Shift+N

Follow these steps to turn on the incognito mode:

Click the wrench menu .
Select New incognito window.
A new window will open with the incognito icon in the top left
corner. You can continue browsing as normal in the other window. You
can also right-click any link and select Open link in incognito
window.

Browsing in incognito mode only keeps Google Chrome from storing
information about the websites you’ve visited. The websites you visit
may still have records of your visit. Any files saved to your computer
will still remain on your computer.
For example, if you sign into your Google Account on
http://www.google.com while in incognito mode, your subsequent web
searches are recorded in your Google Web History. In this case, to
prevent your searches from being stored in your Google Account, you’ll
need to pause your Google Web History tracking.