More than a few definitions of Behavioral Marketing floating out there, but roughly it's the ability for the marketer to discern intent based on actions. And this is directly applicable to Recruiting, i.e., based on what you receive or what you send, intent could be discerned. Here are a few examples:
1) We've all received those emails from college recruiters that come from mailing systems, not from the domain of the sender. However, those mailings systems provide metrics to the recruiter: who opened the email, who clicked on links in the email, etc. And if they're smart (and some of them are), they'll be able to track visits to the college web site from the email through Google Analytics or a similar package. So Player X receives an email from College Y. Player X opens, clicks through to the web site, visits a few pages, and leaves. That's data going back to College Y. Moral of the story: your actions may communicate intent or lack thereof.
2) These same capabilities are available to you, i.e., using third party email systems, you can send emails out and track who has opened them, who has clicked through on one of your links, etc. What do you think the value is to you knowing that Coach A opened your email, clicked through to an online resume or clicked to view video, then forwarded it to a colleague? This really solves one of the great mysteries of Western Civilization: did Coach read my email?
3) I'm not suggesting that you stop sending attachments, but you'll want to put your content online: easier to update, easier to track (you too can install Google Analytics: free and easy). The creation of a web site that acts as a baseball resume is very easy today...and cheap. In addition, you are not restricted to a one pager: different menu items provide your recipient with different places to go, and you can track where they've gone, e.g., you have more hits on video than you do on stats, or your fall schedule has more page visits than any other page, etc.
Just a few examples of the technology that is available to you today...and being used by recruiters. And its inexpensive and (relatively) easy. If the technology proves daunting to you, then have your son do it: he needs to know this stuff anyway!
