www.atheistnexus.org <-- gets automagically linkified (even when not explicitly trying to create a link)
w w w.atheistnexus.org <-- doesn't, but looks ugly.
How to defeat this?
Trying to insert a Unicode "Word Joiner" (invisible nonbreaking "space", like except zero-width) in between the w's ( ⁠ in HTML mode, or equivalently, the decimal form ⁠ instead -- it looks like these get parsed and replaced by the character they represent early, even when switching from HTML to WYSIWYG. Let's see if it works....
www.atheistnexus.org <-- ??? we'll see! suppresses the linkification!
And so should www⁠.atheistnexus.org (with the Word Joiner entered in HTML mode):
(Disadvantage: the Word Joiner is still an extraneous character, and can be a visible "unknown character" -- question mark, or rectangle, etc., perhaps with weird spacing -- if copied-and-pasted into a word processor or text editor. Is there a parallel to Wikipedia's <nowiki> tag?)
Trying another approach: interrupting the magic string "www." with an HTML comment:
www[EDIT: that exposed a bug, which truncated my posting at that point! I'm pretty sure HTML comments inside regular text, not being linkified, are OK... testing it here between these two asterisks: **]