Does PlainText transmit data securely? Does the iPhone App PlainText transmit data securely (i.e. does it use SSL?), or it there a risk of my data being read by third parties when I sync with dropbox?
On dropbox's web site, it says:
All transmission of file data and metadata occurs over an encrypted channel (SSL).

Furthermore, data send over the 3G cellular connection uses a 3G over-the-air encryption protocol (which will likely be unencrypted for forwarding to the internet past the cell tower).