Most pages on NL allow comments to be added. This is your way of addressing something that is being discussed. Like any other type of content, think before you post.
One of the most common problems with comments is that they are off-topic. For example, someone may have asked about were to buy a part for their car and someone adds a comment asking about importing their car. The result is that it becomes harder for new users to find information and typically redundant information gets added.
Another common problem in comments is a personal attack. If you disagree with what is being said, offer facts that support your position. If you make a personal attack, don't be surprised if your post gets deleted. If you continue to make them, don't be surprised if your privilege to make comments is also deleted.
While I recognize that there are some people in the world that know absolutely everything, I suggest that you may find another place to brag about it. We will somehow get along without your help.