How Do I Use Certain Rules / Enable Tests

Does SpamAssassin support real-time blacklisting systems like mail-abuse.org?

Yep, support for these is built-in, and shipped in the default configuration.

All of the free BL services are enabled by default. However, note that if you're using mail-abuse.org, and you're installing SpamAssassin for site-wide use, you must license their services; mail-abuse.org is now only free for personal use.

Note that SpamAssassin still works very well without using these two services, however.

Using Razor / Pyzor / DCC

See UsingRazor, UsingPyzor, UsingDcc.