I am not a lawyer. However, I am in business and have known many lawyers (and have had up to three different types of lawyer on speed dial: Business and contract, child custody, and criminal (we were prosecuting a former employee).
Unlike all other topics of advice in writing, it is my understanding of the law that it can be a crime (in the USA) to give legal advice without BEING a lawyer, especially if that advice is relied upon and the result is the commission of an offense (a crime, slander, libel, copyright violation, etc).
To dispel a common mistake committed in a previous answer, the fact that many other people commit an offense is not an excuse for committing the offense. Ask anybody that has ever had to pay a traffic ticket!
Legal advice requires a different standard of care.
It should be qualified as being not by a lawyer, and an understanding of the law. It does not make a difference if this should be assumed by readers, or should be obvious. Posts that definitively claim something is protected under the law should be either removed or edited to indicate they are an opinion.
Preference should be given to those with links to trustworthy blogs by actual publishers, lawyers, legal websites, universities or state or federal descriptions of actual law in a state.
Amateur legal arguments about the intersection of (American) rights of free speech and what counts as libel or slander or sexual harassment or what people should be "allowed" to sue over should be deleted, if no links are provided.
I will point out that the law on lawsuits seems to allow lawsuits for virtually any purpose whatsoever, and in my own business experience being served with a lawsuit starts the clock ticking on very expensive lawyers immediately (and even if covered by insurance, can take days and weeks of time), and it is generally time and money that will never be recovered. An amateur's ignorant assurances that somebody is safe because "it sounds like free speech" to the amateur, or "no jury would convict you", or "that cannot possibly be how the law works" are simply false.
First, some terrible injustices are encoded in the law!
Second, by the time you get to a "jury" or even a judge (in the USA) you might have spent $25,000 on lawyers. Even if no damages were assessed, I think it is doubtful this money can be recovered: Here is an article written by an attorney that discusses frivolous lawsuits; or suing because you were sued. Excerpt:
A weak lawsuit is not necessarily a “frivolous” one. Frivolous lawsuits are typically cases that have no legitimate factual or legal support and are not even based on a good faith argument for the extension or reversal of existing law.
[...snip...] Bring a suit or claim for “abuse of process.” If you believe that a lawsuit was brought against you for an improper purpose,
[...snip...] Sue for “malicious prosecution” after you defeat the frivolous case. After you have successfully defeated a frivolous case that was brought against you, you might have a basis to sue the one who brought that lawsuit under the theory of “malicious prosecution.” To bring a valid case for malicious prosecution, however, usually requires proof that the suit you defeated was brought with malice and had no probable cause.
Again, it is my understanding it is very difficult to prove a person suing you for damages had no legitimate cause to sue you. Their lawyers would most likely have laid out a plausible case within the law to take it to court in the first place!
Personally I think we should flag some answers as Legal Advice Without Disclaimers, or Legal Advice Without Authoritative Reference.
As for the types of legal questions allowed, I agree with posters that a plausible case should be made that the question is directly related to writing and does not apply to life or business in general, and is not a "cheat" of that, e.g. "My character is being sued because his lawnmower threw a stone and struck the neighbor's car, with his neighbor standing there, and the lawsuit says this required $2,528 in repairs, which my character considers ridiculous. What should he do?"
Of course that might be flagged as "asking about what to write", but would be (to me) clearly asking about a legal question, not a writing question. On the other hand, whether or not a blog post constitutes damages IS a writing question about the law, and with appropriate disclaimers and authoritative reference, should be allowed.