>Aside from old cluttered websites, what's wrong with sites like that? Does the website really matter if all you use it for is to get the number to start a conference call, for free?
Everything is wrong with them, they are a scam, it's called "traffic pumping" [1]. Google Voice and other VoIP providers will block calls to those numbers.
Free conference call services like freeconferencecall.com have local US numbers in high tariff rural areas, usually in Iowa (like the 712 area code). To you the call is "free" because you have Free Nationwide Long Distance. But your phone company has to pay ridiculous rates, as if it was a 900 number, like over $1/min. If you don't have free long distance, than you have to pay those rates.
The Local Exchange Carries in those rural areas have contracts with these scam companies, giving them a take of the money. Or the LECs run the scam businesses themselves.
Legitimate businesses and consumers are being ripped off. The legit phone companies are required by law to route your call there, and they are required to pay the ridiculous fees.
[1] http://en.wikipedia.org/wiki/Traffic_pumping