A truly effective program, not only in grammar and spelling, but does much more: - Assistance in writing (including detection of anglicisms and the register of "familiar" language, for example) - Dicos a package. - Fits in a lot of software, both word processing, desktop publishing as well as most browsers and email programs (mail) - At the same time it can be installed on three computers Windows or Mac OS (example for me: 2 Windows and Mac OS X)