[proexploit]

Use it only when you need a new tab/window to open and nowhere else. You don't want to try and make a user's life easier by guessing if they'd open a new tab, because some won't want to.

The only place I've used it in months is on Facebook iFrame applications where otherwise avoiding it would cause a larger page to load in a smaller area and get cut off.

As another poster mentioned, it would be good to mark as opening in a new window with an icon or text. When it's a small bit of information (like a couple paragraphs of help text), I always appreciate a modal window or tooltip first.

[Omni5cience]

"The only place I've used it in months is on Facebook iFrame applications where otherwise avoiding it would cause a larger page to load in a smaller area and get cut off."

Which would be the "target" attribute's intended purpose, frames that is.