Do traffic exchanges hurt website's Google Search rank?

[jbishum]

I'm the webmaster of an airsoft website that's seen much success in the past 5-6 months with search engine rankings. It's been on the first page results for several of the biggest search engine's for many of my top keywords. I was receiving lots of traffic from search engines (google esp.) until just about a week ago when my website simply dropped off the map on Google.com. It's still listed, but it went from 1st page results to "I can't even find them" results. About a month ago I became a member of a traffic exchange program to help boost my Alexa Ranking. My question is this, do traffic exchange programs harm your google search engine ranking? I can't really find any other reason why it would have dropped so quickly! Thanks for your help!