That old saying is a little misleading. There is a good argument that knowledge is always good; the more one knows the better. The old saying comes up a lot in my line of work. I hear from people who have seen material online that tells them a little bit about how the legal system may work, but it is not helpful, or downright harmful to their case. The info they find online may be completely wrong or it may be true for a different state or a different type of legal situation than what they have.
Doing your own research online can be a good supplement to the legal advice you are getting or a way to gather background information. Be careful though, just because it comes up on your computer does not mean it is always true. Anyone can post anything online even if it is not fact checked. We all hear about wacky online conspiracy theories and false information floating around online. You do not want to go to court and quote false information or information that may be true for a different state, but not the one you are in.
When you are online, clicker beware.
Ed