Today was the big day! Twitter is officially a public company, as the service opened up for public trading on the New York Stock Exchange this morning. In its short seven years, Twitter has essentially changed the way we communitcate with each other. To call the company revolutionary would be a gross understatement. With a growing and devoted user base, Twitter has become perhaps the second most important social medium of this generation (Facebook still holds top-dog status—for now, anyway). As expected, the tweets were on fire, and we've collected some reactions to the #TwitterIPO here. Enjoy Twitter for now, because it may never be the same after today.