The Apple II initially was used mainly for running video games. Its popularity considerably increased when Daniel Bricklin wrote a program called VisiCalc – the first electronic spreadsheet (computerized accounting program). Other types of application software were soon developed for PCs. Because personal computers were much less expensive than mainframes, they could be bought by individuals, small and medium-sized businesses, as well as by primary and secondary schools. The era of personal computing began in earnest2.