I don't know if it's that I'm getting old compared to the rest of Hacker News or if I have a different life but sending calendar invite to friends for events (lunch/dinner) seems fairly standard. A typical week I will probably have something scheduled most evenings, same for my friends. I wouldn't see most of them if we didn't plan for it.
I agree; was surprised that someone bothered to blog about it like it's a life hack, but there you go. I think there has been some loss in transition between the calendar we all had hanging on the fridge to doing the same in a more digital time.
