Silent Bob is the silent partner of the Jay and Silent Bob duo. As it is widely known, Silent Bob is played by Kevin Smith who writes, directs and/or produces the Jay and Silent spectrum of movies.
As far as the character goes, the name "Silent Bob" should clue you in on the key feature already. Silent Bob is quiet. He normally speaks one time during the course of a movie and this single line becomes quote fodder for the legions of Kevin Smith fans. This is in stark contrast to Jay, Silent Bob's sewer mouthed, forever yapping partner. The only other staple of Silent Bob is the ever present trenchcoat--enlongated by a foot of extra fabric for added coolness.
Even without the benefit of dialogue, Silent Bob contributes to every movie. Whether it's blueprinting the destruction of game shows in Mallrats or throwing angels out of speeding trains in Dogma, Silent Bob isn't afraid to get his hands dirty. Plus he has cool toys like a Batman issue grappling hook and Jedi powers.
It really doesn't matter what he wears or carries--it's the quotes that make Silent Bob awesome. Ironic, no? Here we go, per movie, listed in chronological order.
Silent Bob: "There's a million fine looking women in the world, dude. But they don't all bring you lasagna at work. Most of 'em just cheat on you."
Silent Bob: "Adventure, excitement? Jedi craves not these things."
This is Silent Bob's longest speech by far. It is actually too long and in accordance with the wishes of the powers that be it has been taken down. If you want the summary, just know that years ago, Silent Bob had a girlfriend Amy whose sexual history scared him and he flipped out and pushed her away. He realized too late that his supposed inadequacies were not and she really wanted to be with him. But it was too late and she was gone. Since that day, Silent Bob was been chasing Amy.
Silent Bob: "No ticket."
rootbeer277 reminds me that this is a copy of Harrison Ford's delivery after throwing a Nazi out of a Zeppelin in Indiana Jones and The Last Crusade.
Silent Bob: "The sign on the back of the car said 'Critters of Hollywood', you dumb fuck!"
Silent Bob: "Oh, but I think it is. We had a deal with you on the comics, remember, for likeness rights. And as we're not only the artistic basis but also, obviously the character basis for your intellectual property, 'Bluntman and Chronic' when said property was optioned by Mirimax Films you were legaly obliged to secure our permission to transfer the concept to another medium. As you failed to do that, Banky, you are in breach of the original contract. Ergo, you find yourself in a very actionable position."
Silent Bob: "I got nothing."
I haven't seen Clerks 2, so if there are other Silent Bob quotes in there, the internet lied to me.
Apparently, Silent Bob was supposed to be, ya know, silent. As noted above, Clerks was the first movie that featured Jay and Silent Bob. Consequently, this is the first time Silent Bob speaks. However, the line "There's a million chicks..." was supposed to be spoken by Jay. Unfortunately, Jason Mewes, who plays Jay, could not get the line out correctly no matter how many times he tried. Since the budget for Clerks was so small (making the soundtrack cost more than shooting the movie), the crew could not afford to waste any more film stock on Jason's bloopers. Kevin Smith stepped up as Silent Bob to deliver the line correctly and break the character's silence. Kevin Smith did not want to do this, but it turned out to be the most outstanding, poignant line of the entire movie. Fan response was so overwhelming that Kevin Smith made this a function of Silent Bob in all subsequent movies.