YouTube

2005–2011
The logo consists of the black word "You" and a red rounded rectangle with the word "Tube" in it next to it. This logo is still being used on some other pages.

2011–2013
This modification of the YouTube logo was introduced in July 2011 as a part of the Cosmic Panda experiment. It officially became the new logo a few months later. It has the red square in a darker color this time. Also, in 2012, the slogan "Broadcast Yourself" was retired.

2013–2015 (primary), 2013-present (secondary)


On December 19, 2013, the red rectangle was made lighter in color. Also, the word "You" was made more black and the shadow behind the word "Tube" was removed. This is still used as a secondary logo.

2015–present (primary)
The gradients were completely removed from the logo in October 2015.

Yoodles
Like Google with their Doodles, YouTube changes their default logo to a stylized one with relevance to a certain date on various days throughout the year. These special logos are sometimes called Yoodles.