I don't know about that. But I do know she crushed it here. Big time, heavy duty. And, the more I think about it, there's really no need to partner with Twitter.
Mayer appears to be setting Yahoo! up to stand on its own as a "daily habit" (her words) or one-stop shop (my words) for all things social. The stuff that's on Yahoo! now and has been for years -- the stuff most of us use everyday -- is inherently social.
Expect Mayer to partner where she needs to, but ultimately compete with Facebook and Twitter. Yahoo! has what it takes to make that happen. If the reborn Flickr foreshadows the future of a Marissa Mayer-led Yahoo!, more companies than the wholly social animals ought to look the bleep out.