Show Link: Link will be shown in full, highlighted blue. Most pastes should have this option.
References: Each link will be replaced with numbers and will be shown in full at the end of your text. Use this if you want your links to work like Wikipedia references.
Numbers: Each link will be replaced with numbers and will be shown throughout your text. Use this if you have links with huge URLs.
Count: Show a number next to all links, counting all links from the top.
None: No links will be clickable, use this if you want to post code.