I first installed Dropbox on my home computer, my work computer, and my iPhone. It was a great way to share documents between the three devices. Once I was having a conversation about a picture I took on my Nikon camera. I wanted to show the person I was talking to the picture. I called my wife at home and asked her to drag the photo into the Dropbox and within a minute I was showing them the picture on my phone. Then I emailed it from my phone to the person I was talking to and it ended up being used in the newspaper.
Dropbox runs in the application tray in the bottom right corner of my PC or top right corner on my Mac.
When I click the icon and then the Dropbox folder it opens a window on my desktop just like any other directory window. I am able to drag and drop as-well-as cut and paste into the folder.
The same files are also synced to my Iphone where I can view and use them.
When we got our new computer for my wife's job we only had one printer but wanted to have the kids use the older computer for there homework and other computing needs. With Dropbox having only one printer is not an issue. The kids do what they need to on their computer and then put the files into Dropbox and can print them from the new computer. [I know I need a newer printer].
I also use Dropbox for genealogy. I got a hold of some family photos of my wife's relatives and I scanned them to use in my genealogy program. When I was finished I added all of the images to a folder in Dropbox and then sent a link of that folder all to the relatives in that family. They could follow the link and access only that folder in my Dropbox and get the photos without having to got through kids homework, church talks, and letters to my missionary. It was also safe and secure.
I also use Dropbox to backup my Legacy database files [you can see the files in the folder image above]. Since Dropbox works like any other folder on my computer I point the backup tool in legacy to the Dropbox folder and the rest is easy. The added advantage to using this to backup my files is that I also run Legacy on my laptop, so I can open the backup files on my laptop and update my legacy folders and then both of my computers are in sync.