Have you ever wanted to go back in time? I know the first time I watched Back to the Future I was very intrigued with the idea. As much as I'd like to think our generation will see this technology, we won't. It's far to complicated and even if it was possible, we would use it poorly and probably end up erasing our entire existence.
So if we couldn't go back in real life, second best would be going back in time on the internet right? Just nod your head, I've got a point here I promise. A cool site called the WayBackMachine has been archiving a large number of websites (old and new) since around 1996 and the search engine there allows us to check out the catalog. Have you ever wondered what Microsoft's page looked like on October 20th 1996? How about the initial version of Twitter as seen on September 30th 2006? The archive includes a ton of publicly accessible social media pages (Hi5, Nexopia, PlentyOfFish etc.) where you can view old profiles and various tidbits of information.
This could be a useful tool for someone doing a school project or research on a specific company. However it does shed some light on just how unforgiving the internet is, as once something goes public online, it could be found whether you delete it or not.