It's easy to allow visitors to the site to email you (and without revealing your email address, which protects you from spammers):
- Login to the site
- Click on the "my account" link in the menu below your username on the right side of the screen
- Click on the "Edit" tab
- Scroll down to the bottom of the screen and click on the "Personal contact form" checkbox
Now when site visitors view your profile, they will see a "Contact" tab that allows them to send you an email via a web-based form. Check out the a profile for an example of this.