Got ya. You may try to come up with a way to do the demo without the email address for users. If I had just stumbled upon the site, and thought it may be someth

Got ya. You may try to come up with a way to do the demo without the email address for users. If I had just stumbled upon the site, and thought it may be something I would use but was not quite sure, the first thing I would do is try the demo. If I immediately saw it ask for my email address I would feel like you are scavenging addresses and move on to another site. If you absolutely require an email consider clearly stating that up front and the reason why an email address is needed for the demo to function.