Several big services have had outages longer than 4 hours in a row during the last year. A big hosting data center burned down completely. Such outages just h

Several big services have had outages longer than 4 hours in a row during the last year. A big hosting data center burned down completely. Such outages just happen. Of course Yahoo offering their service for "free" (i.e. some moderate price paid in customer data and advertising annoyances) won't necessarily make any efforts to tolerate them.