What is the best practice on whether/when to open a link in a new window/tab?

Question

Is there a best practice on whether or when to open a new link in a new window/tab (versus forwarding the current window/tab to the new link)?

Answer 1

It is good practice to open the link in a new window/tab if:

1. The target is on another website and the user is likely to continue browsing your site after following it
2. The primary purpose of the link is to print the content, so it contains no navigation
3. The link is a detour from a standard workflow (ie a help page in the middle of a mutli-step form

Answer 2

A good guiding principle in web design is the back button. It's the one piece of UI that virtually all web users know how to use.

Thus the only appropriate place to use links that open new windows is in states which can't be easily reached by the back button.

A prime example of this is links in the midst of forms:

If the users click on the form then the back button will not get them to the state they were at - with the form being partially filled.

This is not to say that target="_blank links are the only or even a particularly good solution to this problem, but they are the one place where users are expecting them and they can be actually beneficial.