Want to guard against spam? Want to make sure sensitive information isn't easily nabbed by an automated script?
Use Enkoder for Drupal! This uses the logic behind Hivelogic's Enkoder to encode any field or arbitrary text in a recursively self-evaluating block of javascript, foiling all but the hardiest of spambots.
You can use this to harden any text-based field and this module also exposes a general-purpose php function (sclib_enkoder) for your own custom uses.
In my examination of the Drupal module landscape, SPAM-hardening solutions either tend to be focused on forms (like CAPTCHA) or provide very limited email encoding (such as by providing HTML entity encoding or exposing an input filter).
By using this module, you
can arbitrarily harden any core text field, even ones that don't use an input filter
can arbitrarily harden any text, not just things look like email addresses.