If you send a mail from Hotmail’s web mail (Wave 3), recipients will see a one-line Hotmail ad below your message text. In the upcoming Hotmail version, e-mails sent with Hotmail will no longer have an advertisement footer. The update, rolling out from 15 June 2010 onwards, is code-named “Wave 4”, and getting rid of the Hotmail advertisement is part of this new version.
I do not want to be forced to choose sending all my mail through Outlook just for the sake of getting rid of Hotmail’s advertisement footer in every single mail I send. This thought is the main reason for the Windows Live team to remove the advertisement bar entirely. Now it is up to you to send mail via Hotmail or a rich client — your recipients won’t notice the difference anymore.