Thomas Edison invented the word 'Hello' as a greeting. Previously the word was 'hullo' (note the spelling) and was used as a term of surprise: "Hullo, what's that?" Edison thought 'Hello' was a very clear word and used it as introduction when testing his electronic equipment.
It is not a useless fact its history with out that guy i would be outta job alone with a dip in profit for 50%-70% of business phones play a big part in business. Sales, Support.