When it comes to multiplayer games, I'm the definition of noob... I think I've played around two hours total of COD4 and MW2 multiplayer. My experience with MW2 went something like this: Spawn -> take 3 steps -> get killed by an airstrike -> repeat. I'd pretty much written off multiplayer in general.
 
But thanks to some serious boredom last night, after some runs against bots to boost my confidence, I gave team deathmatch on Black Ops a run, and actually had a really good time. I joined multiple lobbies over the course of three or so hours, and I didn't hear a single racist/homophobic rant, or run into any screaming kiddies like I'd feared. What's even weirder is that I was only 75% useless; after a few rounds I was consistently scoring in the middle of my team, and even managed a positive kill/death ratio a few times. 
 
My question: can this last? Was it beginner's luck? Are the better players playing different game types? As the game is out longer and people learn the maps will I go back to being cannon fodder? Just wondering how multiplayer communities for these games usually evolve.

All depends on the lobbys, the players, the gametype and many other factors.  You probably just suck at playing well and jumped into a lobby of new players and got lucky.

Play more, play with people you know and unlock better guns. I was like you, I was playing for shit, bullets weren't registering and couldn't get a handle for the guns, but once I unlocked more things and got better guns and perks, my k/d finally went into the positives so just keep at it but I wouldn't recommend playing with randoms anymore.

I can totally relate. I played it online for the first time last night and started terribly but got better as I went along. To answer your question: No it probably won't last. Not unless you play it incessantly to learn the maps and generally keep your skills sharp.

 The more you play, the better you get - it's that simple. There's no real formula to getting better, but if you play a lot, you learn the maps well, you get better responsively, and you just get into frame of mind. It will last, so long as you keep playing.    Good COD players haven't figured something out, or are blessed with sheer natural ability, they just play a lot. 

Stick with the multiplayer for a bit and see how you feel. The glory of small sample sizes is that anything can happen. Who knows, maybe last night you were playing worse than you normally would, and you are in fact a better player than you thought. You'll never know unless you keep at it. Play enough so that you have a big enough pool of games to really judge how good you are at the game.

Another suggestion is learn where people tend to go (most people do the same things in the same spots). Think "When I go around this corner, where is the other guy most often?" For example, maps like Firing range have some spots near the bathroom (along that long side) where there's obvious cover at the corners, and guys are almost always there. Go around the corner and aim to those spots everytime, regardless of whether you think someone is there. It doubles as practice if there's nobody there to kill.

You'll get familiar with the formula the longer you play. You'll get better, but so will other players. Just keep playing and you'll do alright.

It's easy to do well if you follow these simple tips:
 
1. Use a silencer. Get used to it. If you're a red dot on the map, you're already dead.
2. Stay at the edges of the map. If you can't get flanked, your survival rate will sky rocket.
3. Don't run and take it easy. Running around a corner against a walking enemy gets you killed.
4. Don't play if you're getting annoyed. You will just die over and over at the same spot.

I've played a good 500 hours of CS and I still suck at it, but that's kind of a SFII syndrome thing: People have been playing that game for so long that anybody with less than 1000 hours is going to get murdered (at least that's what I keep telling myself). MW isn't like that yet, I think that there is still time to break in. Yeah you'll get killed, but there aren't a lot of people who are super-veterans running around.

" @EricMartens: If you're playing on your own, I recommend playing Mercenary stuff. That way you won't run into groups of people who just rape. That what I do since I have no friends who play. That way you'll play with people who are in the same boat as you (at least being alone). "

I say just keep playing multiplayer, and you'll keep getting better at it.  If you don't like to play games with other people that's a lot of value lost from games.  You'll sometimes get in matches with really good players and you will have a hard time, but don't let it frustrate you.  As long as you don't care about losing or dieing then you'll have fun.  Also try the wager matches, that stuff is fun like when everyone has crossbows or random weapons.

I was absolutely terrible at Call of Duty until about my 4th prestige in Call of Duty 4. The only reason I stuck with it was because I played with friends and, even though I was dying a lot, I was having fun.  
 
You'll get better with time. 

Play defensively. The problem I have is running into people who usually have guns with better range than I do. After that, you should focus on being able to sense, and react quickly to any sort of motion within (and outside of) your field of vision.

Defensive is the way to go, also keep in mind, this game is always faster than you want it to be.

Multiplayer takes a few round to get used to for almost any game. I just usually play defense for a while, and then play offense when I'm more used to the game.
 
You have to play quite a bit of a game to get good at it.

My XBox Live motto is "I Know I Suck"
 
My K/d is currently something like 0.66, but I'm having a heckuva good time. Some of that is because I've gotten to play with all three of my sons which is a new thing (split screen + multiple live accounts is very very cool).  Some of that is because the maps are fantastic, and some of that is because of the unlocks and ranking system.

Maps make or break a game
 
Thankfully Ops has the best maps I have seen ever for the series so this will help me and others stay glued
 
Unlike MW2 which was a futility in frustrations do to the bland campy maps

Learn the maps, unlock some weapons and then decide again.
I was ready to also burn this disc as I did MW2's but I unlocked some more weapons and now it seems I'm doing way better.

Black ops has bots right? It's there for a reason. But just keep playing, you will eventually get good at it.

I'm in the same boat as you. I can get pretty good if I play every day but unfortunately I can't. So I usually end up jumping into games, sucking hard and then stopping. But the bot thing looks somewhat promising. I can see myself playing mainly bots and then jumping into online games every once in awhile or when friends are on.

" It's easy to do well if you follow these simple tips:      1. Use a silencer. Get used to it. If you're a red dot on the map, you're already dead.  2. Stay at the edges of the map. If you can't get flanked, your survival rate will sky rocket. 3. Don't run and take it easy. Running around a corner against a walking enemy gets you killed. 4. Don't play if you're getting annoyed. You will just die over and over at the same spot. "

" Maps make or break a game  Thankfully Ops has the best maps I have seen ever for the series so this will help me and others stay glued  Unlike MW2 which was a futility in frustrations do to the bland campy maps "

10,000 hour rule. Play your game enough and you'll eventually gather some sort of skill.

Thanks for all the responses... been playing the last few nights and reached level 20. I'm still in the middle most of the time, rarely (but occasionally) dead last, and definitely still enjoying myself. Having a wife and daughter is going to keep me from becoming a full-fledged pro at this game, but I'm having a good time, which is not something I ever thought I'd say about a multiplayer game. A big thank you to Treyarch for putting the bots in here. Without some practice against them I highly doubt I'd have ventured online at all. Wish more games did that (ahem, Halo). They also did a nice job with the progression stuff; always earning random XP from challenges makes the level grind seem faster for some reason.
 
Oddly, a lot of people recommended that I play with folks I know, but my MW2 experience taught me that was a bad thing. Everybody I know is in the same married/kids boat and just as bad at the game as I am, but the matchmaking kept putting us all on the same team. Which is probably why every round turned into Airstrike Fiesta. After each round, the other teams were literally begging us not to leave their lobby (or calling us fags). I guess I could try the Mercenary mode with friends, but most of my friends seem to have skipped this CoD. Ah, well.

I've given up trying to come out tops in this game and am resigned to the fact that I am very average at CoD. Not the shittiest but not the best either. I'm happy to accept landing in the middle of the scoreboard on 90% of matches. I'm 30, have slower reflexes than a 16 year old and don't play the game 24 hours a day. Once I gave up worrying about my K/D and how many times I died, I generally found myself less stressed out and doing much better at the game and enjoying the game a shitload.

i bought the game and jumped into multiplayer first and i was doing amazing, then i played the campaign all the way through and i suck again at multiplayer, it always gives me such bad habits

Just wait until December 26th when all the irresponsible parents get their screaming children copies of Black ops as it makes their lives easier than dealing with their own hellspawn and well see about how quiet,polite and non-racist the community has become.  Im just enjoying it as much as I can before then. Wish MS could have mature player matchmaking system, hell id even pay a few more bucks a year for one. Oh well.

" Just wait until December 26th when all the irresponsible parents get their screaming children copies of Black ops as it makes their lives easier than dealing with their own hellspawn and well see about how quiet,polite and non-racist the community has become.  Im just enjoying it as much as I can before then. Wish MS could have mature player matchmaking system, hell id even pay a few more bucks a year for one. Oh well. "