YouTube’s traffic dipped for the second week in a row, with the world’s biggest video-sharing site reporting 29.7 million unique users for the week of Jan. 13, according to Nielsen Online. That’s down from 30.7 million for the week ending Jan. 6.

MSN Video may have lured some of the traffic away from YouTube. MSN Video’s unique visitor count hit 3.3 million for the week ending Jan. 13, up from 2.5 million the week before.

Yahoo Video dipped to 1.4 million for the week, down from 2.2 million the week before.

Week-to-week fluctuations are common in online video.