In case you missed it:
If you’re using Yahoo Mail, you don’t have to worry about attachment size limits anymore—you can now access your Dropbox from right within your email account.
You can add files from your own Dropbox to any message, and you can save stuff people send you back to Dropbox as well. And the integration does away with file size limits, so you can send giant photo albums around to your family at will. That is, if you are actually using Yahoo Mail.