At this point in history, I think we can safely say that there is no way to guarantee anonymity on the internet. There are ways to make it harder for interested people to figure out who or where you are. (Posting to Whisper via Tor, perhaps -- though I imagine that wouldn't be wise to do on a military base.) But if a company handling your data and/or a government really wants to identify you or at least your location, they can. Am I right?