According to the Skype documentation the only effect is the "Creator" tag but I'm not so sure about that.
This option has to be enabled before the options JOINERS_BECOME_APPLICANTS and JOINERS_BECOME_LISTENERS can be set.Also, this cannot be disabled while one of the JOINERS_BECOME_xxx options is still set.Enters the administration mode of the chat (only if creator) and adds a small text "Creator" to the user-icon in the chat.I didn't find so far a way to leave this mode again.
If you have knowledge of more of those commands or about the ones with a question mark please leave me a note in the comments.
"/alertson text" sets the skype notification to occour on special text in messages. If an alert is set, every instance of the text will be highlighted in the chat window for easier detection of the alerting lines.