Q:

How do I prevent auto-generated links in the GitHub wiki? 

On a GitHub wiki page, if I type:
www.foobar.com

GitHub automatically assumes this is a URL and makes the text a hyperlink to http://www.foobar.com.  However, sometimes I do not want a hyperlink to be created.  Is there a way to stop this behavior?  Perhaps some sort of markdown? 

A:

This isn't limited to wiki page, and is part of the GFM (GitHub Flavored Markdown) url autolinking feature. 
Putting them in `` can work but display the url as a code: foo http://example.com bar. 
foo `http://example.com` bar

Another trick (mentioned in this gist) is 
ht<span>tp://</span>example.com 

That will display http://example.com as regular text. 
In your case (without the http://)
w<span>ww.</span>foobar.com

That would also display  www.foobar.com as regular text. 

A:

Also, if you are having a issue with something other than a URL auto-linking I found escaping the .  works as well.  
Example:
foobar.web -> foobar&#46;web

A:

You can also just apply a backslash escape to the colon (or any of the other punctuation, apparently), like this:
http\://www.foobar.com

