No, because they send
real, interested visitors. They do not ask
you personally to visit other members sites in exchange for traffic in return. You put the banner up to send real visitors, that aren't you or people you know, in exchange for real visitors to your site.
The word 'exchange' isn't the key distinction. The way the traffic is earned and received is. If you personally are asked to visit 30 other peoples websites in exchange for 30 visits from other members then you are in a bad service. Banner exchanges (trustworthy ones at least) are the same as Google Ads, but are paid for by putting the code on your site. If you buy traffic from the sites you listed you are essentially doing the same as advertising on a real ad network like Google AdWords.
Some examples of Traffic Exchanges (the ones to stay way from) can be found at:
http://www.trafficexchangelist.com/Additionally click exchange sites are even worse. They are basically the same set up as a traffic exchange but instead of just exchanging visitors you are asked to click the Google, VCM, Yahoo, MSN, etc ads on each site you visit. This is called click fraud and is illegal to all ad networks.
Here is more information on Wikipedia:
http://en.wikipedia.org/wiki/Traffic_exchange