You faked thousands of dropbox accounts, created thousands of fake mailing lists and it seems you bogged down parts of the network. This may not be terribly destructive, but it is reckless and borderline malicious. Someone at MIT and Dropbox will now have to spend their time checking their systems for your manipulations. It may have been fun, but I don't think it was worth it.
It's MIT and Dropbox... I'm sure internally MIT can handle a one thousand new mailing lists at any given occasion (until they are deleted), and I'm 100% sure Dropbox didn't even notice a blip on their network as a result.
And also MIT don't have to check for anything. They deleted everything when they were done.
I don't know why it was such a big deal for some MIT students to feel like they have to win the Spacerace either, but I did actually enjoy the article, although I'm not sure why the effort was made in the first place either.
MIT probably has 100,000+ emails registered. A couple thousand accounts that each get one email sent to them doesn't make much of a dent. The post mentioned the purposeful renaming of lists to avoid being obnoxious. Combine all that with it all happening earlier sunday morning and I doubt it had much effect on the network.