I don't agree with DNQuest.com. Sony have applied to trademark "Blu-Ray" but -
1) the mark hasn't been granted yet in the categories they have applied for and bearing in mind they applied in 2005, my best guess is other electronics companies objected strongly.
2) the categories applied for don't preclude anybody selling, renting, or reviewing Blu-Ray movies from a website, online Blu-Ray forums and communities of interest or any anything else a web developer would want to do with a domain with the term Blu-Ray in.
This extract is from the USPTO.gov website;
"Optical disc players and recorders for audio, video and computer data; blank optical discs; pre-recorded optical discs featuring music, movies, games, text data, still images and motion pictures; television sets; video cameras; digital still cameras; personal computers; digital satellite broadcasting systems, namely, receivers, transmitters and antennas for satellite broadcasting; video game machines for use with televisions, all for use with optical discs as recording media"
3) Even if the above was not the case, and it is, Sony is hardly likely to go after people with Blu-Ray domains that promote their technology when there is a format war going on. That's free publicity and marketing for them.