Hi TBiz,
The fact with these website is the following: they have a lot of sitewide links (link that appear on more then one page of the linking website). For ex, footer links (such as "created by" or "designed by", etc.), advertising which appears on each page, etc.
Although it can drive a big number of inbound links, I would still go and ask the question of quantity vs. quality? Which one is better for a website? (If it would be me, I would choose quality).
I hope that helped,
Istvan