My ad has a code next to my phone number that says begin_of_the_skype_highlighting and end_of_the_skype_highlighting. What is skype highlighting?

Depending on the ad-on for the web browser, your browser may insert Skype code automatically during the ad placement process around your telephone number. To disable the Skype coding, you will need to disable your plugin on your web browser. Consult your Skype manual for instructions on disabling this browser plugin.