The number of paragraphs is not what they mean by something meaningful. Some posts are long and have multiple paragraphs that are still meaningless.
When they say post something good it means you should say reasonable stuff. There are newbies here that just come to the forum and start educating others on how to use the forum. It shouldn't be so. There's a thread that was saying on how newbies should learn instead of trying to teach people about the forum.
Make reasonable contributions instead of just saying meaningless things.