Re SA no longer on Yahoo, Marissa probably first tried to acquire SA as that is her style. It would make sense too as SA has built a large user base and recognition. A deal likely could not be reached and so the 'Plan B' on tumblr, which has a checkered reputation.
Time will tell whether SA or Yahoo is hurt more.
For me, it takes away some of the utility of Yahoo knowing that it will not show all things published on a stock. I will use google finance and msn money more now, as well as having a browser instance always set to the SA home pg, which refreshes itself on stories published on your portfolio.