Legal Question in Personal Injury in California

You very well may be able to do so. This is a type of case involving the law of "defamation". Often, the greatest difficulty in this type of case is actually proving the loss. There are time deadlines which can keep you from recovering, so you need to get going fairly quickly, and you should do all you can to document the actual postings for use later.

It's possible but not guaranteed. You can certainly sue the person for libel, but there are defenses to libel, such as truth and opinion. And except under some limited circumstances, you have to prove actual, and not speculative damages. Finally, if you are by any means a public figure, the rules are different, and you have to prove "actual malice" (a deliberate disregard to the truth) in order to win.

One more thing: Google the "Streisand Effect." By getting litigious regarding slander you will draw more attention to it, guaranteed.

In theory, yes. Whether you would actually be successful depends first on whether the person has the assets to pay such a large judgment without simply declaring bankruptcy and cancelling the debt. Next it depends on whether there is admissible evidence that proves 1. the person you sue is the person who posted the lies, 2. that they are in fact lies and not opinion or other forms of expression that are not specifically false statements of fact, 3. that the false statements of fact were the actual and direct cause of your losses, and 4. the amount of your losses directly proved to have been caused by the lies. If you have clear and convincing evidence in a form that is admissible in a court of law that proves all those things, then yes, you can. If any of that is missing or not provable, however, then you can sue but you will lose.

You can sue, but what matters is whether you are likely to win. That will depend on many factors, some of which my colleagues have already identified in their answers. Explaining all of them here wouldn't be practical. You should instead discuss your claim one-on-one with an attorney. She will be able to offer meaningful guidance once she knows more about what happened.

Please feel free to contact me directly if you want to discuss your case in detail.

Good luck.