DOTA 2 beta keys now also have TWO DOTA 2 Gifts that you can send to friends, so that they can play with you. Here is how to invite them:
1. Log into your Steam account.
2. Open the Steam window.
You can right click the Steam icon and select any of the following: Store, Community, Library, News.
3. Select “Games” and “Manage Gifts and Guest Passes”.
4. Select one of your DOTA 2 gifts and press “Send”.
5. Pick if you want to send it via Email or through Steam.