One of my favorite websites is badmovies.org, a site dedicated to the discussion and mockery of b-movies. Reviews of these films, complete with clips, stills, sounds, and hilarious commentary are to be found therein, along with a lot of other germane film information. Try it and you'll be hooked even as I was.
Per Wikipedia we find:
A B movie is a low-budget commercial movie. In its original usage, during the Golden Age of Hollywood, the term more precisely identified films intended for distribution as the less-publicized bottom half of a double feature (akin to B-sides for recorded music). Although the U.S. production of movies intended as second features largely ceased by the end of the 1950s, the term B movie continues to be used in its broader sense to this day.
Most B movies represent a particular genre—the Western was a Golden Age B movie staple, while low-budget science-fiction and horror films became more popular in the 1950s. Early B movies were often part of series in which the star repeatedly played the same character. Almost always shorter than the top-billed films they were paired with, many had running times of 70 minutes or less. The term connoted a general perception that B movies were inferior to the more lavishly budgeted headliners.
And so here we are. The owner of the site referenced is a film enthusiast, a very patient man, and possessed of a keen wit. His commentary is priceless, as seen in the following example, this concerning 1957's Attack of the Crab Monsters, a B-movie if ever there was one (and available on YouTube):
I've spent hours looking through this site, just to see what has been said about old films with which I am familiar, and I am impressed. Give it a look to see if your old favorites are covered. Note that it isn't static and entries continue to accrue, supplemented by guest commentaries. There's quite a bit to explore, so get going.