Why supplementals won't go away

This could be why

[tiori]

Maybe this is old news to some; but the "light bulb" just went on with me on this.....

Suppose you had a page named abc.html that was one time indexed properly and then went supplemental.

At some time in the future you decide to change the name of the page to def.html

You think the correct thing to do is to make a 301 redirect for abc.html to def.html since you want eveyone to know that the old page has moved.

All good so far? Not really; as I've discovered, Google still thinks that the supplemental page abc.html exists.....because it was redirected to def.html and assumes since it gets a header of 200 ok as a result of the redirect that the abc.html page is still alive.

Not sure what all this means, but it could have something to do with why some sites remain all supplemental after doing a 301 redirect for non-www to www

The supplementals may live forever unless the 301 redirect is removed.