Jakob Nielsen way back in 1999. and again in 2005

Opening up new browser windows is like a vacuum cleaner sales person who starts a visit by emptying an ash tray on the customer\'s carpet. Don\'t pollute my screen with any more windows, thanks (particularly since current operating systems have miserable window management). If I want a new window, I will open it myself!

With an exception for non-Web documents.

Mark Pilgrim from Dive Into Accessibility

In all dominant browsers, using the []{target="_blank"} tag to force a link to open in a new window *breaks the Back button*. The new window does not retain the browser history of the previous window, so the \"Back\" button is disabled. This is incredibly confusing, even for me, and I\'ve been using the web for 10 years. In 2002, it\'s amazing that people still do this. Don\'t do this. Don\'t force links to open in new windows.

Please note that this tip is about you as a web designer, not you as a web user. If you want to open new windows while you browse, go right ahead. In Internet Explorer for Windows, hold down the [Shift]{.kbd} key while you click a link to open the link in a new window. In Netscape 6 and Mozilla, hold down [Control]{.kbd}. In Internet Explorer for Mac, hold down [Command]{.kbd}. (Some browsers such as Opera support advanced combinations like [Control]{.kbd} + [Shift]{.kbd} + click to open a link in a new window in the background.) The point is that the choice of whether a link will open in a new window should be the end user\'s choice, not the web designer\'s choice.

[More]{target="_blank"} practical advice from Brainstorm & Raves

Consider the target audience, allowing for the less computer- or browser-savvy. More savvy users already know they can press the [SHIFT]{.kbd} key when clicking on a link or right-click on a link to open it in a new window. For less savvy users, you could provide separate links for opening in a new window or the existing window, along with letting them know they can download it for offline viewing.

And finally, a good list of 5 reasons why you should avoid this and why this practice won\'t really keep users around.

Here are my top five usability reasons why you should beware of opening links in a new window:

1. Unless you warn them, web users are likely to expect the new page to load in the current window. Unexpected surprises can be fun, but not when you\'re browsing the web.

why this practice won\'t really keep users around.

Not on its own it won\'t. Web users will stay on a website because it has the information they\'re looking for, or because it helps them achieve their goals, not because the browser window is still open.