Anybody can look that article up by using google, I presume.
You can edit a post for something like 10 minutes, and then you can't.
If you need to add more tags to the ones someone else kindly provided, then add your own. They may or may not take, as usually it is best if you tag them yourself when you ask a question or add a discussion, but sometimes more tags will show up (replacing those there) if you add several of them. Others can add tags too. Only five tags are seen under the title, but they still are somewhere in the system.