Facebook, on my setup (OS X, Chrome) takes about a 1 second to close. I can imagine that there could be some stuff that has to be done, just before you close the browser, and that is taking up time/resources. However, I've started to wonder if something like this could not be intentional? What is the effect of a site that takes time to close?
On the one side, I can argue that making a site take time to close (non-instantaneous) creates a barrier to leaving. It is an annoying grievance that the feedback is not quick and responsive, so as a user, you want to avoid it, by keeping it open.
On the other hand, that grievance can have an opposite effect: the perception that Facebook is bloated and slow. My last experience of it was that it was unresponsive, so I don't want to come back.
Or is it both? A continuum? A very small 'lag' can have the first effect, but making it longer is more annoying? Or is it just not a good idea?
EDIT: For clarification, I'm referring to the closing of a browser tab.