They were originally a do-everything Internet company like Google, but without the aura of smugness and infinite amount of ad money. (My friend who was a Yahoo Search sysadmin tells me they had nearly as good results as Google on much, much smaller amounts of hardware expenditure.)

At some point they tried to become a media company or something and did hire a lot of journalists, but they kept making the wrong moves and trying to acquire users by buying unprofitable websites like Tumblr and eventually ran out of money.