And I agree with this 100%, but that's not an SEO reason, it's a usability reason. Any references or research to back this up? It's something that comes up in the office here occasionally, and although we all agree that using - instead of %20 looks better, we've never been able to find any SEO reason why %20 are bad. Has anyone actually done any research on this, testing or asked anyone at Google's opinion? I see people saying 'it's bad for SEO' but nobody ever says why
I know hyphens are classed as word delimiters and underscores are not. I can't see any reasons why Google would know know that %20's not delimiters either - pretty cut and shut if you ask me. A note from the earlier post, bots certainly do not have trouble parsing urls with "special" characters such as %.
Just to add to that too, search engines ignore everything after a # in a URL because it just shows the same page and the search engines know this. MSN didn't too long ago and it was very easy to get competitors banned for dup content