Jay and Silent Bob Strike Back spotlights two characters who've appeared as a comedic thread in Kevin Smith's movies: Clerks, Mallrats, Chasing Amy and Dogma. The characters worked well in small doses. They work fairly well in a 95 minute film completely devoted to them, but it's just not the same.
One of the things I liked about Jay (Jason Mewes) and Silent Bob (Kevin Smith) is that they indicated a permanence to whatever visions director Kevin Smith was dreaming up. In this film, it is the rest of the characters and stars from previous films that return. This sets up a whole bunch of cross-references which can get pretty confusing (though I'm sure someone on the web has made a complete list of all the connecting threads).
The plot is just a showcase for Jay and his heterosexual life mate Silent Bob to be idiotic: the two slackers find out that a movie about them that is based on the comic book characters they inspired, Bluntman and Chronic, is being made by Hollywood. They decide to hitchhike to Los Angeles from New Jersey and prevent the film from being completed.
Jay and Silent Bob Strike Back is clever for the pop culture references it makes. While not all such references are of high calibre, some are stand-outs. More than the pop culture tributes and parodies, the highlight of the film include extended gags that involve rescuing an orangutan and taking care of it, as well as the application of the George Carlin rule when hitchhiking.
Kevin Smith likes to do similar things again and again in his films, which lends a familiarity to his work that has created a pop culture aura around itself. These include his references to Star Wars, Steven Speilberg, comic books, and ice hockey. Thus watching one of his films is like being let on an "in-joke". Whatever; but it is also a good marketing ploy. I recommend checking this out with friends who've seen his other films.