A member is defined as a child who has gone on to earthrangers.com, filled out a full contact form, received parental permission, and then actually been sent a membership card with their name on it and a welcome package in the mail. They have then logged into their account numerous times to actually accept missions that are sustainable behaviours and to participate in fundraising campaigns, so they really are defined as an engaged group of people who are acting with the organization on an ongoing basis.
Then we have kind of a sub-level of kids whom we know we've reached and impacted in some way. For example, I was coming home from an Earth Rangers event and stopped at Loblaws on my way home. The girl at the checkout counter saw my shirt and remembered us in her school and the assembly from six or seven years ago. She never joined, but it impacted her in some way.
You're right that the reach is a lot more extensive than 300,000, but the 300,000 is defined as families that have signed up.