You did not mention the version of Acrobat. However, Reader XI does not require Activation to save a completed form. In addition, there is a restriction of the use of the extended feature (see the license) for 500 uses of the form. At this point in time, I would not recommend the use of the extension unless you can be sure of the restricted use.
You can mention that Reader XI allows for the form to be saved. As far as submission, you can do that with a submit button and only submit the form data (there is no need for the entire form as you can import the data to the form on your end and then add to a database). With the FDF data format, you can even use the FDF toolkit to manipulate the data directly to add to a database.
If your file will contain any personal data, e-mail should not be used as it is not secure. You should have the data submitted to a secure server for your use, but then you have to be able to write the server side script for this need. The FDF toolkit has examples for such scripts in several languages.