How can I open an external link in the SAME window (adding %target=_self% doesn't work)?

You shouldn't need to add anything, normally external links open in the same window. If not, check if you don't have set a custom $UrlLinkFmt variable (which shouldn't contain target='_blank').

• Interesting. I have an external link set up in the sidebar and when I go to the wiki and click it behaves as you say but after I edit the side bar (don't change anything or even save just click cancel) it then adds the external link icon to the link and opens it in a new window! Refreshing doesn't revert it. The only way to 'reset' it is to enter wiki from the link on another page. Very odd but not overly inconvenient. Weird that the external link icon disappears too. I've done no link variables.
• Ok now it is really annoying as the behaviour changes not just when editing the sidebar but when entering edit on any page.

Make sure you close the %target=_blank% [[link]] with %% every time, or else all subsequent links in the same paragraph will open in new windows. Also, a skin or a recipe may modify the $UrlLinkFmt variable to force a target=_blank attribute. --Petko? April 14, 2009, at 10:36 PM

How can I make a link back to site where I came from (like the button in the browser)?

How do I give a link a Tool Tip? eg [[Links"tool tip"]] or [[Links | here"tool tip"]]

See PITS:00657 and Cookbook:LinkTitles.