Media embedding change

[marta]

Due to an exploit that took place through media embedding (lj-toys), we temporarily disabled that feature this evening.

At the present time, we've re-enabled media embeds only for two sites:

http://www.youtube.com/
http://video.rutube.ru/

We will have a post in news shortly to explain the exploit and what occurred, and will add to the media whitelist over the next few days.