Join for FREE,
and start talking with other members, weighing in on community discussions,
Also, by registering and logging in you'll see fewer ads and pesky
welcome messages (like this one!)
Another way colleges check on "showing interest" is through the emails they send. They can monitor if you open the email or simply delete it without opening it. The more deletes, the less interest, the less likely an admit decision.
If this really is the current game in college admissions, I'm surprised so many kids/parents choose to play.