AcademicEarth

AcademicEarth is similar to the previously mentioned YouTube EDU in that it organizes videos of college lectures.  But the similarities stop there.  AE hosts only six institutions (Berkely, Harvard, MIT, Princeton, Stanford, and Yale).  It places an emphasis on lecturers and lecture topics, instead of institution.  It's easy to find lectures on a topic of choice or lectures by your favorite lecturer.  Furthermore, AE provides entire courses, not simply stand-alone lectures.  My favorite course, so far, is The American Novel Since 1945 by Yale's Amy Hungerford.  The course page even lets me access the class syllabus and final exam.  

YouTube EDU

YouTube EDU is a section of YouTube that organizes YouTube's university-sponsored channels.  Each of the channels is basically a pool of lecture videos from each particular university.  Most of the universities provide less than 100 videos, but some provide close to 1000.  My main complaint is that I can't find a way to sort the EDU videos by topic.

Vimeo

Vimeo is a video site similar to Youtube. But Vimeo is different from Youtube in two key ways. First, Vimeo allows for higher-quality videos. It supports consumer-HD video (720p), and, compared to Youtube, videos with higher average bitrates and resolutions. Second, Vimeo only hosts user-created videos. No commercial videos (like movie trailers, sports highlights, or music videos) are allowed unless the submitter was involved in the video's creation. Vimeo also prohibits gaming videos and pornography.

These two differences have created a Vimeo community that is markedly different from Youtube's community. Judging from the comments and the videos, the Vimeo community seems to be more of an artistic crowd, producing interesting, unique, and beautiful videos; helpful criticism and nice comments; and a culture of unity and achievement.

Some of my recent favorites include: One Year in 40 Seconds, Green, and Her Morning Elegance.