Random Thoughts: Time Spent

For the last few months Mo and I have been pushing the concept of engagement rather than numbers when it comes to website statistics / analytics. One of the main pieces of that engagement puzzle has been time spent. In talking with some peers over the past few days I noticed that most viewed time spent on page as a good thing. However, I wonder what the other site of that argument is...if someone is spending a substantial amount of time on a page does that mean they cannot find what they are looking for?

Is more time spent always a positive (good) metric, or can it be a indication of an issue with the site?

Has anyone encountered this issue? Thoughts?