Who does Launchpad notify when I upload a source package?

It depends. Launchpad sends out two emails in the most common case:

 * a package being uploaded to the release pocket of a release which is open for development
 * an upload which passes all of the required tests
 * an upload which does not need intervention from the distribution managers.

Of those two emails:

 * the first is sent to the distribution release's changes list
 * and the second is sent to people associated with the changes file, who are:
   * the signer of the changes file;
   * the person listed in the Maintainer field;
   * the person listed in the Changed-By field.

If a selected email address is associated to a Launchpad account that is a member of a team permitted to upload to the distribution (ubuntu-core-dev for Ubuntu, for example), it will receive a notification of the upload.