There is a lot of information on the internet. Asking questions on forums and social media is natural for many people when they want to find something out.
One time you might need information is if you suspect you are under criminal investigation. You might be concerned about how the investigations or the noise around them could affect your reputation and your business as well as your freedom. Hence you may turn to the internet perhaps asking others if they have ever been investigated for a particular thing. Or asking questions based on hypothetical situations (which just happen to be similar to your own).
Investigators may see your activity
Let’s say you work in the financial sector. You post questions that are aimed at fathoming whether or not one of the transactions you made or some of the advice you gave could land you in legal trouble. Your postings are all very hypothetical but you might inadvertently give away some information that relates to the actual transactions you made.
Investigators and prosecutors often check social media and online forums for leads on a case. Maybe they will create a false account on the site you are posing and ask leading questions to try and squeeze a bit more information out of you that they could use to pin you down.
The information you find may be wrong
A helpful poster gives you a detailed reply based on their experience, or based on what they know. That does not mean the information will be true for your case or that it is correct at all.
The internet is not your friend if you are worried you are under investigation. Far better is to turn to someone with the appropriate legal experience and standing who can look at the situation and guide you on the next steps to take.