Once you've placed the screener, you have a number of ways that you can activate it.
Before doing anything though, make sure you've turned your screener on! If you are unsure of how to turn on your screener, read this article.
Make sure you enter it as close as possible to that "</body>" tag as possible. From the 'Activation' page in your screener setup, you can adjust a number of things like the frequency at which the screener appears. And since we're aware of how difficult it can be to get any code placed on a site, we've created some documentation that will hopefully help you in your ethnio quest.
2.) A Link to Email or tweet or put in an ad or on Craiglist or wherever. There is a nice short direct link that you can use to send the screener via e-mail, IM, or even Craigslist if you're brave enough. Here's an example of what that looks like.
3.) Native App Intercept for iOS or Android. If you want to have an intercept in your app, you can totally do that. Learn more here.