You've probably heard of Dropbox by now. If not, the basic premise is that it's a place for you to store files in the cloud, so that it's easily accessible from, well, pretty much anywhere you've got a network connection. That means I can save a file at the office, and pull it up at home to continue working on it. Or on my phone or ipad in a coffee shop on the other side of the world. 1
A more specific use that I have for Dropbox is photo backups, for the photos on my iPhone. I think they give you 2GB of free space when you sign up, and will give you another 3GB if you download the app and allow it to automatically copy every photo in your camera roll to your Dropbox. Frankly, this is a no-brainer. Be like Nike: just do it.
One final specific use I have for Dropbox is syncing settings. The most important of these is 1Password. This way, I can add a login on my ipad when I sign up for a new service and - once it syncs - I never have to worry about adding it on my computer or phone. Through the magic of Dropbox sync, it's just there.
In fact, I'm using it right now. I write these posts on my ipad when I have time and save them as text files to Dropbox. If I haven't finished a post, I can pick it up on the computer at home or just call it up on the ipad for further editing later. It's a simple, but very powerful, concept. ↩