From the Terms & Conditions:
You agree that you will neither use the Site in a manner, nor Share any Content, that: (a) is false or misleading; (b) is defamatory, derogatory, degrading or harassing of another or constitutes a personal attack; (c) invades another's privacy or includes, copies or transmits another's confidential, sensitive or personal information; (d) promotes bigotry, racism, hatred or harm against any group or individual; (e) is obscene or not in good taste; (f) violates or infringes or promotes the violation or infringement of another's rights, including intellectual property rights; (g) you do not have the right and authority to Share and grant the necessary rights and licenses for; (h) violates or promotes the violation of any applicable laws or regulations; contains a solicitation of funds, goods or services, or promotes or advertises goods or services; or (j) contains any viruses, Trojan horses, or other components designed to limit or harm the functionality of a computer. Oracle may report you to the relevant authorities and may act under the fullest extent of applicable laws if you transmit or upload content intended or designed to cause harm.
Particularly clause b - basically, be nice.
If you're not nice, your posts will be deleted. If you persist, you will be blocked.