I'm not sure when this practice began, but I've first seen it done with Mystery Science Theater 3000. It's a practice generally aimed at very low-budget horror/sci-fi flicks, mostly from the 50's, extending into the 70's (MTST 3000 has used at least one 70's movie that I recall). This was of course the TV series broadcast on the Comedy Channel, later moved to the Sci-Fi Channel. The show (as everyone knows) used a party of 3 (a human and 2 robots) watching the same movie the viewer is watching, all the while making verbal mockery for all to hear, while we see their silhouette sitting in the front seat of the movie theater they are apparently forced to occupy. Since then this practice of extra sound effects is commonly seen in Late-Night horror movie TV host themed programs that feature LNHM hosts like, Mr. Lobo (Cinema Insomnia), Wolfman Mack, and Svengoolie. Sound effects are added to B-movies, which at times include added visual effects which bring comedy relief. The subtle mockery theme of old B-movies prior to adding effects to the movies, I'm not sure when it started. Judging from the movie "Ed Wood", it appears that the 50's horror movie host Vampira may have utilized this practice, at least to some degree, judging from a phrase used in the movie suggesting that Bela Legosi was another unknown has-been. As a kid I remember a local horror movie host known for his dry humor, and average-man appearance (no costume or make-up to appear goulish), by the name of Bob Wilkins who hosted a Saturday night show called Creature Feature, who promoted the movies he would show as bad movies, with the intent of projecting a humorous side to early horror/sci-fi B-movies. And since at least then, this theme has caught on, possibly in an attempt to prevent these B-movies (no matter how bad) from meeting utter destruction. Off-Beat Cinema, a B-movies late night syndicated show out of Buffalo, hosted by 3 hosts made up to appear like coffee shop beatniks, utilize a clever artistic analysis of each movie, as if they took the movies seriously. Is all of this good or bad? My opinion is that it's all good, except for one problem....... Why do they only pick on the old B-movies. In fact, why just pick on B-movies? There are a lot of modern, relatively high-budget movies, like "Pearl Harbor" that should be fodder for this type of practice. There are probably modern movies I would watch only if they were tampered with by a MST 3000 type production.