There are three integration points: - Share from Dropbox: when composing an email, insert a link to a file already in your Dropbox. - Save to Dropbox: when

There are three integration points: - Share from Dropbox: when composing an email, insert a link to a file already in your Dropbox. - Save to Dropbox: when reading email, save a received attachment to your Dropbox. - Upload to Dropbox: if you try to attach file over the 25MB attachment size limit, you're given the option to upload it to your Dropbox and link to the file on Dropbox.