"The "invention" represented in the '842 patent is starkly at odds with the real history of technology, accessible in this case via a basic Google search. EFF lawyer Daniel Nazer, who wrote about the '842 patent in this month's "Stupid Patent of the Month" blog post, points to an article on a Microsoft publicity page that talks about quirky out-of-office e-mail culture dating back to the 1980s, when Microsoft marketed its Xenix e-mail system (the predecessor to today's Exchange.)
IBM offers one feature that's even arguably not decades old: the ability to notify those writing to the out-of-office user some days before the set vacation dates begin. This feature, similar to "sending a postcard, not from a vacation, but to let someone know you will go on a vacation," is a "trivial change to existing systems," Nazer points out. But patent lawyers have long been able to add trivial features to well-known technology in order to get software patent grants."