I just removed the external tag from a question regarding viewing of source code for a browser, and it got me thinking that this is somewhat a meta-tag.
There exists tags such as external-hard-drive and external-display, and most current external tagged questions are related to these or similar external devices.
The tag was also mentioned in the Tag cleanup for January 2013Tag cleanup for January 2013 post.
Should we burninate this tag?
UPDATE
It is back, with 100 questions tagged for it. I suggest black-listing it as well
