On Tuesday night, during a dinner conversation about the growth of Facebook and the potential of Twitter, I tossed out a phrase that I can”t get out of my head these past three days at FortuneBrainstorm Tech in California. The conversation was with a dozen or so Silicon Valley execs, from companies like Google (GOOG) and eBay (EBAY) and Palm (PALM), and they were noting that Twitter hasn’t invested much in talent — given its global prominence as a communications platform and its need to become a sustainable profit-making company.

So what, it doesn’t matter, said one smart executive at the dinner, contending that “virality” will propel Twitter’s success, at least for a while. “Virality is virility,” I replied. More in Pattie Sellers’ Postcards blog.