I recently stumbled across an oddity while debugging a transmission problem. When I searched for "transmission-daemon Error loading config file", I got the same askubuntu question on both the first and the second spot.
I'll shorten URLs to make it more readable, assume them all to start with
The second one has the answer ID of one of the provided answers attached. Why Google chose to request that URL or index that, I don't know. It appears that it doesn't even have to be a valid ID, i.e. you can just request
and get a perfectly fine 200 OK with no robots meta-tag (or header) and no indication that this isn't the main URL that content is available at.
I've also noticed, that this doesn't happen if you add something to the URL without a leading slash, i.e.
will redirect to
with 301 Moved Permanently.
Is there a reason for this behavior?
I would've thought that Google would be smart enough to realize it's identical content and drop the version that is less often linked to, but it appears not to, or at least not consistently (I haven't stumbled upon this before).
I don't see any advantage in doing it this way vs either adding a canonical tag (works extra great with askubuntu, but the problem exists on all sites) or telling search engines to only index the main version should be an easy fix.
It's not a huge deal, but there's no reason to give even more weight to the StackExchange network on google by hogging multiple spots with the same content.