Okay, I currently have 7 (or 8) open Evites. If you don't know what an Evite is...it's an electronic invitation. There are so many great things about Evites...I love them. They probably aren't etiquette yet, but I love them all the same. You can tell when someone gets them (and looks at it) and you can see every persons immediate response. Plus there are always the funny people who like to give their witty one-liners on why they will, or won't, show up at said event.
However, there are always the people who don't reply...WHY NOT?!? You've seen the invitation, you can at least reply "maybe" and let the organizer know what you are waiting on...spouse conversation, babysitter, desire to attend, waiting to see if the person you want to see (or don't want to see) is going. But I think everyone should reply as soon as you get the Evite. I mean, it's bad enough when you don't RSVP to an event and then show up, but isn't it just as rude to see an Evite, not reply and then still show up??
Okay, that's my opinion on that. Most people will tell you I'm the first to reply to Evites, maybe I'm the only person who thinks it's rude not to.