The flickr username is not the same as your yahoo username. They are linked, but can be different strings. You sign in to flickr using your yahoo username (ie, your @yahoo.com email address) but your flickr username is a completely different string.
The reason for this, I suppose, is that flickr was an independent entity, with its own user database, before being acquired by yahoo. It was long after the acquisition that yahoo insisted on linking it to your yahoo ID. Some will remember the brouhaha that caused.
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The flickr username is not the same as your yahoo username. They are linked, but can be different strings. You sign in to flickr using your yahoo username (ie, your @yahoo.com email address) but your flickr username is a completely different string.
The reason for this, I suppose, is that flickr was an independent entity, with its own user database, before being acquired by yahoo. It was long after the acquisition that yahoo insisted on linking it to your yahoo ID. Some will remember the brouhaha that caused.