Some good reasons why you shouldn’t blindly follow the “external links open in new windows” mantra which seems inexplicably popular, mostly through (it seems) arrogance:
- If you don’t explicitly specify that the link will open a new window, the behaviour is unexpected. The vast majority of links don’t open new windows, so you’re violating the principle of least surprise.
- Some browsers (notably Internet Explorer, the most popular browser on the planet) take what seems like an age to actually open the window; lots of behind-the-scenes memory allocation has to happen before the new window is useable.
- Opening a new window breaks the “Back” button. The “Back” button, on most operating systems and browsers, is far more visible and prominent than the “Close” button, and unless the user knows the site they were browsing prior to clicking the link is still there, clicking “Close” will be an absolute last resort. Moreover, anybody who’s ever worked support will be all too familiar with the “never closing windows” syndrome, where users regularly end up with upwards of thirty open windows because they’re completely oblivious to the concept of closing them.
- You’re achieving the opposite intended effect: the justification for opening new windows is “I don’t want to take them away from the site”; leaving aside the flaws in this argument alone, the fact is that you’re encouraging them to start along an entirely separate browsing session that is away from the site they started at.
Opening new windows and tabs has its place, but in 99% of cases, it should be a matter of user, not designer, choice. If it makes you happy, add “Tip: Hold down Control (Command on a Mac) while clicking links to open in a new window”. Admittedly, this isn’t perfect (it assumes users are “clicking”, for a start), but it’s still better than forcibly opening new windows whether the user likes it or not.
Further reading
My opinions count for little, ultimately. Fortunately, it turns out that this one is shared by many people a lot cleverer than I:
- Not Opening New Windows—Dive into Accessibility
- Beware of opening links in a new window—Webcredible
- Avoid forcing to open in a new window—webnauts.net
- DOM:window.open # Usability issues—Mozilla Developer Connection
- Opening new Windows with JavaScript, version 1.2 [particularly note the green “Update” panel at the bottom of the post]—456 Berea Street
- Web Content Accessibility Guidelines 1.0 # Interim solutions. Until there’s a standard way of allowing users to prevent windows from opening when the designer specifies it, the WCAG’s recommendation is that you shouldn’t do it.