Read the article...
First off, let me wish you a congrats on the award, Milena!
Interesting ideas presented here. I would like to read the original article. I am particularly interested in this: "More interactive features can be added to improve the shopping experience," [Hassanein] says. Such features could include mimicking 'mall shopping', by allowing multiple remote users to shop on the site simultaneously, like friends going to the mall..."
This would be very popular among teenagers, I have no doubt. You would have to add a chat feature too. He considers the trust factor, but I would add that you should certainly consider the "coolness" factor if you are going to develop this sort of an environment. Consider your average mall: is it not jammed full of teenagers, dressed in clubwear, trying to hook up? I see it often when I go shopping... in fact, it's a large part of why I dislike shopping.
It would be interesting to examine The Sims Online in this context, and in particular, all of the associated expansion packs. There are malls and restaurants included to the neighbourhood. I would be willing to bet that there would be some patterns here that could be mimicked to provide a good start for the creation of a suitable online mall.