Yahoo was first started by Jerry Yang and David Filo in February, 1994. It did not start as a search engine. In fact, they started it to keep track of their own interests online. Later it turned into a simple catalog which contained the site links in the Internet.
The project was initially named as Jerry’s Guide to the World Wide Web. In April the name of Jerry’s Guide to the World Wide Web was changed to Yahoo. Yahoo is actually an acronym for Yet Another Hierarchical Officious Oracle.
WHY ! AT THE END OF YAHOO??????
At that time “Yahoo” was already trademarked by a company that produced barbecue (BBQ) sauce, knives and human propelled watercraft. For this reason Yang and Filo added the exclamation point to the end of Yahoo!