There's many many ways to ensure your site will be blacklisted;
1. Utilizing malware/exploits
2. Developing/distributing 
3. Using unethical means to promote a site or program
4. Utilizing hijacks
5. Utilizing blackhat SEO techniques
... etc etc etc etc
The list goes on and on and on.
Another method however, of ensuring you'll be blacklisted, is by spamming through compromised e-mail accounts. This is a method gtomart.com decided to use yesterday when either themselves, or someone associated with them, decided it a good idea to compromise my other halfs e-mail accounts (not a good idea, especially when you're going to spam everyone in her contacts list - as that includes me - woops!).
The two e-mails I received contained;
Both of these sites have one thing in common - they both redirect to Chinese owned gtomart.com (126.96.36.199 - 188.8.131.52-static.reverse.softlayer.com, AS36351 184.108.40.206/18 SOFTLAYER - SoftLayer Technologies Inc).
WhoIs for gtomart.com;