I often find links on sites that open a new window rather than opening in the window that the link was found in. I can only assume that the web designer made the assumption that they know what the user wants better than the user. What they have effectively done is create a reverse “pop-behind” advert to themselves which is a bit mad when you think about it. Given the choice I will always use normal links on my sites.
If I want a site to open in a new window then
I will make that decision myself. Who are you to tell me what I should be doing.