A good thread to revive Mercenary.
I recently said smoke needs to last longer and be thicker to be as effective as it should, everyone seems to agree that point.
It's unfortunate smoke's effectiveness happens to diminish when people use bad graphic settings, quite ironic as the better players may be regular gamers and have a better computer, so it is infact newbies shooting you

Ok, not exactly true.
Different colours technically could help, white smoke isn't as good at concealing someone wearing black. Probably much less important than the previous problem. Still smoke with different colours (rather than the radar grenade) would have made the game a bit more...colourful. What, they ran out of coloured smoke by 2142?
The concealment effect is only useful if that concealment is more important than being as aware of your enemies as you would otherwise be. Which is why it is mostly used for assaulting.
Concealment
Throwing smoke which you promptly run into to obscure the opponents sight on your exact position. It is used with
the sole intention of keeping you, and anyone else inside, alive for longer, most likely to allow you to move further, either
to natural cover, or a flag.
The upside of this trick is exactly the same as it's downside. A cloud of smoke which is hard to see through and the enemy will all be aiming at.
The enemy are
aiming at the smoke not you because they, hopefully, cannot see you. Bullets hit you less, rockets and grenades may not land as close as the enemy hoped.
By taking less damage you might get to the desired position.
However, they are now all looking at the rather obvious smoke, which you currently reside in and they know it. A lot is being fired at you, although the chances of being hit by anything when your opponents vision is impaired even slightly, must be less than it would otherwise be.
Once at your destination you do not use the smoke. Behind a new piece of cover or at a flag you are mainly stationary or in a general area,
smoke will now do more to obscure you're awareness of enemies and reduce your ability to fight back, than it will to help you. They all know where you are and without moving you are just begging for rockets and grenades. But the point is you have made it to where you wanted to be, hopefully a strategic location.
Yes, the smoke also lowers your awareness of the enemy while running...but you shouldn't be trying to see them, you should not even be aiming at them. The more you were to shoot back the less sprinting you would do, but you can easily smoke and run at the same time (as long as you don't develop a nasty chest cough that stops you in your tracks

).
If you were to fire...then you are simply fighting your way and not sprinting, which is entirely different. The better one is just down to which gets you past.
Blocking Enemy View
Throwing
smoke on your enemies is a good thing
when they are in cover:
Because,
your squad knows where they are (or you can tell them).
You don't need to hit a person directly with a grenade or rocket to damage/kill them. Bullets will be hard put to hit their mark, but the smoke does not reduce the effectiveness of your squad's use of explosives by much at all while they are still. The radar, and the small area they are in, should easily get your shots close enough. This is even better if you were already looking at them and know exactly where a particular person is.
If the enemy moves while still behind the cover you
follow them with the smoke.
If they move
out of the cover they have
lost that advantage and
you don't need the smoke.
It follows that the true
advantage is that the enemy, hopefully,
cannot see you at all...as people have already said seeing out of smoke seems harder than seeing in. They need to hit you dead on with bullets so they are now down to
lucky shots. Explosives have to at least be near you, the direction may be known well enough (assuming you're staying still while smoking/shooting), but
their depth perception is reduced dramatically.
Admittably, the radar can cure this for their grenades if they're good enough, but
rockets are renderred near useless as everyone has to aim at some object or another at distance; which they should no longer be able to see.
Thus, it is
their awareness reduced considerably more than your own and this tactic
only requires one or two people with smoke, supplies possibly needed, and the rest are free to rocket/grenade the opposition.
Smoke As A Distraction
Unfortunately with such dismal smoke grenades it is quite hard to fool squads with this tactic, especially TGers.
By throwing the
smoke immediately nearby, anyone already shooting you will simply continue to do so and will know a squad has not moved into the smoke.
You may be able to distract people who were not already shooting at you: You must
remain unseen behind cover and then distract those who will see the smoke before they see you. Because the smoke is very noticeable it will catch the opponent's eye; as they look, they now notice you. They have to aim at where you're going to be, most likely, the smoke. In that crucial moment you can
change the direction you are running. As this only lasts a moment, you should
move behind cover immediately.
Camp G gets a mention at this stage, it's a perfect example because before you move out of the uncap as Pac, it is hard to be seen. By throwing smoke, say, on the other side of the ramp and running up it at the same time: pretty much everyone looking at you is assuming you're going to use the smoke as cover and is aiming there. Having not seen you until now
they have no idea how many may be following and
you may invite more attention than you deserve 
and for a number of seconds (especially if they think you are a squad leader) you will be
occupying some of their team while yours does something else.
You could use this to
have your squad scatter at the moment
multiple smokes go up, completely ignoring its supposed safety and unexpectedly,
opting for natural cover instead. Although ending up partly seperated, perhaps two three's or three two's, it might be
good at assaulting or
moving out of a difficult situation, and anyone who dies will of course spawn on the squad leader (assuming he's up).
One batch of smoke and the trick is up. You cannot keep throwing it,
you are not fooling anyone.
It is
only in conjunction with cover that this tactic will help at all as you need cover to obscure you before smoking and immediately afterwards.
You are
entirely aware of your enemies but
they are taken by brief surprise.
A rewrite for you all...if you havn't dosed off