Will be re-added shortly after patch hits
Blizzard has announced that during the next patch's implementation, streaming trials will not be usable. Streaming is when you would have the game but not have all of it downloaded, so it would download new zones and places little by little for you - while this feature will be reimplemented shortly, perhaps downloading the full trial would be better.
The streaming trial client, which allows trial users fast access to the trial version of World of Warcraft, will be temporarily unavailable while we prepare for our next major content update, "Echoes of Doom." Trial users can continue playing World of Warcraft by downloading the full trial client here. Streaming trials will be brought back online within a few days of Echoes of Dooms release, and we will provide further updates as they become available. Please visit our Technical Support forum for additional information. You can upgrade your account to a full version at any time. Just purchase and install the retail version of the game (available at most software and video game retailers), then enter the provided Authentication Key at our online Account Management service to upgrade your account. After you upgrade you will still be able to play the character you create during this trial. For details about the trial version client, refer to our Trial Account FAQ.
Stay tuned for more updates at Blizzard's site!
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