Anyone heard of these sites?

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I signed up to a few sites yesterday, and before I spent some more time on them: http://www.iwon.com/ - apparently they have a really awesome sweepstakes program and there's a winner every day of 10000 dollars, but I haven't won. http://www.winzy.com/namd3r - a search and win site, it also works like a sweepstakes program, but you can also win instant prizes if you search at the right times. Haven't won anything yet from there either... http://searchchips.com/namd3r/ - another search and win site that is based on earning chips and then "buying" prizes with them, so it's not a sweepstakes. It also has a random instant win when you search. I won 10 dollars to Amazon.com from this site, but I can't tell how many people are on the site or if people have won prizes recently. Anyway, has anyone tried any of these with success?