You have to admire the creativity of the creators of this site. Just the name alone makes it easy to remember. That being the case, many a time I have been at my home site and wished I had access to material at school so I could work on it from the privacy of my house. Having access to sites that I have preselected our using the time of others who have surfed the web for information is a great idea. So for private use, yes, I can see how this site has much to offer.
In regards, to my use of this site as a teaching site or reference site for my students, I could foresee using this option to select sites for research that I have previously audited that would provide them with good information. This would be an easier method than writing web addresses on the board or sending them emails with approved sites. The only constraint becomes setting up the site and maintaining it as the teaching world like many jobs requires plenty of hands on and the time left is very finite. I like the concept but realistically, am not sure how often or to what degree I would use it for teaching purposes. As stated previously, for my own personal use I can see the effectiveness.