Costolo and Mayer obviously know one another from their days together at Google ( GOOG). And Twitter is probably a better long-term partner for Yahoo! anyway. Ultimately, they can help one another out during times of need. Mayer has kicked things off nicely, but she needs a strong platform -- outside of Yahoo! -- to push Flickr forward. And Flickr can pick up exactly where Instagram left off . . . and more. So maybe I do endorse the idea after all. Follow @rocco_thestreet --Written by Rocco Pendola in Santa Monica, Calif.