YouTube, Vimeo and other video sharing sites provide a critical tool for the dissemination of contemporary music. Many pieces that are not available via commercial recording can be found on these sites. Additionally, ensembles are using this resource to educate and expand their audience base. Below are three ensemble channels that I find particularly compelling. Of course there are many more out there, and I encourage you to share your favorites in the comments section at the bottom of the post.
I've chosen to begin with ELISION Ensemble because their YouTube Channel presents an impressive array of videos that are of the highest quality visually and aurally. Every video expertly deploys multiple cameras in a manner that provides an intimate look at the physical realization of the score. This is clearly exhibited in the video below, an excerpt from Liza Lim's solo cello work Invisibility (2009) performed by Séverine Ballon (note the use of a serrated or "guiro" bow - see Tim Rutherford-Johnson's blog for more).
In addition to posting performances, MusikFABRIK's channel offers instructional videos that deal with extended techniques. In the example below, flutist Helen Bledsoe demonstrates and discusses the production of air and percussive sounds. The video includes notation examples with verbal descriptions in French, German and English. These videos are a wonderful resource for composers and performers alike.
Video is an especially effective medium for percussion as illustrated by this Chicago-based ensemble's channel. In the example below, Third Coast performs the third movement (Sextour de sixxens) of Phillippe Manoury's Le Livre des Claviers (1987-88). The sixxen, an instrument first developed for Xenakis' Pléiades, has an incredibly rich, resonant sound that defies description. See and hear for yourself: