Why Do I Have to Log In to Yahoo! Mail Every Time?

He was an outstanding general. He restored democracy in Athens. He dealt with his enemies moderately after victory.
For Pausanias, a travel writer of the second century A.D., he was "the greatest of all famous Athenians", before Pericles. For Cornelius Nepos, a Roman historian of the first century B.C. he was ahead of all others "in integrity, firmness, greatness of mind, and love for his country." For Donald Kagan, an eminent historian of the 21st century, he is "the only Greek I know whose name fits a Yale fight song".
Yet, Thrasybulus, son of Lycus, is forgotten — whatever the reason.
Now, if Yahoo! Mail has forgotten your log-in credentials in addition to Thrasybulus, let's find out the reason — and maybe do something about it with a fight song or two:
›› Even with "Keep me signed in for 2 weeks", you have to log in to Yahoo! Mail manually every time? Here are potential culprits, and what to do about them.