It depends on what you are advertising, how, and where--all traffic is not alike.
All TEs are not alike, either :-).
I have been using TEs since they were invented, and now own one, which is a tale in and of itself. Fortunes began life as a perfectly honorable tax dodge. Unfortunately, it became successful even faster than my last tax dodge. My other half has told me these are two of my very few failings; my refusal to run a business poorly, or run a poor/dishonest business. he's joking, of course, but he's also right.
My members report that they are getting signups from the login ads, and the regular traffic, and I offer some really good benefits to my Nekosamas (the life time members)--including an automatic upgrade and freebies in all my future tax dodges LOL. But Fortunes is evolving into a combination play place, wealth redistribution portal, and stealth sales funnel. It's actually rather fascinating to watch.
If you have a bright, explosive splash and banners, short timers and fun sites work well. I use the old school sites--the ones with longer timers and NO games, contests, zubees, etc., to advertise squeeze pages and freemiums, and sites like funguppy and leads leap--free with good paid options. And both types work well for me. On sites like Fortunes I can chat, play games to win cash and traffic, collect zubees, and find the occasional cool, new, free thing.
On the old school sites, I can surf and examine programs without distraction.
Of the last 10 programs I joined, I found 7 through traffic exchanges of one kind or another, and the other three through Jackpot Viral Mailers. And in the last year I bought 4 digital information products online--2 I ran into through viral mailers, one I ran into on Traffic G, and one I found on Fortunes while surfing.
There are plenty of buyers, clickers, and hard driving types on traffic exchanges--it just takes longer sometimes to run into them.