Carl, technically everyone who creates content and contributes to a written exchange would own what they contributed - or could be considered coauthors in the whole of what was created. But it would be extremely unlikely that any sort of lawsuit would be filed over published conversations of the type found on Facebook pages. It would not be so unlikely if it is a conversation between two famous people or an interview published by, say, a magazine or newspaper.
The words of most people are just not valuable enough to support the costs of an infringement action over emails or letters or printed conversations. Copyright law would cover these words, though, if they were original and creative enough.
The part you quoted, justalayman, says: "When you publish
content or information. . .you are allowing everyone. . . to access and use that
information. ."
I read that as the content remains rights-protected but, once the content is accessed and the information is read, the
information is yours to pass on (by telling others what you read, not by reprinting it). Just like reading a book - you can pass on the information in the book but not reprint the book. The content still belongs to the creator of the content.
I am not seeing that any legal action would be pursued against yankees98a based on what he has written here, but, legally, he would be infringing on copyrighted material. But, if the creator of the content decided to sue for copyright infringement, he could try out his fair use defense.