People always get me with the photon cannon block. Once they get it started, I cant seem to break out of it in any way (its worse now that cannons are 150/150 instead of 100/100). Ive tried seige tanks, but with lack of vision I cant take the cannons out fast enough.

Ive heard that the best way to stop it is to catch it early, but even if I do, I lack the firepower to take it down (marines just dont do enough). Anyone got any tips?

You would scan with your orbital command and then your siege tanks can attack.
You could also probably run up to them if a couple of thors if they do not have a lot of cannons (less than 8?)

If you're actively scouting you should see it coming. You'll know that he isn't spending minerals at his base early on, and should expect something weird like a proxy gate//cannon. You can then react by throwing down more barracks and a bunker at your entrance/nat entrance. If you are contained by cannons, just know that he spent at least 400 minerals on his tech to cannons. For each additional cannon adds another 150 minerals. Knowing this, you can safely tech to medivac and just expo somewhere else, like an island expo -right off the bat. This will match his minerals spent on the cannon tech.

When my partner scouted, we didnt notice anything unusual; however, I think we scouted too early to find out if he was gonna do the cannon block (the opponent had just completed his first pylon). I dont normally scout the area in front of my own base, so I didnt catch it until he already had cannons. I was going with the 3rax build, so I didnt immediately have the tech to counter with tanks and such. I tried the scan, but it doesnt last long enough for my tanks to get more than a couple shots.

Btw, how exactly does bnet decide which league to place you into? I was under the impression before that 5/5 was diamond, 4/5 was plat, 3/5 was gold, 2/5 was silver, 1/5 and below was bronze. However, one of my friends got 2/5 and was placed into bronze.

It's some equation based on who you play. I'm Silver 1 and I've played a placement match.

Yeah, the placement is a little strange.. just think of Microsoft's TrueSkill and there ya' go.

For clarification, I meant I'm ranked 1 in Silver, and being ranked 1 in Silver, I have played someone who was still doing placement matches, my point being that during your placement, you play opponents of varying skill.

Thus, scout your base.

Plus, you should be able to notice that a probe has entered your base to scout. You should make sure that probe is gone.

I never have a problem with cannons inside my base. Its when enemies surround my base with cannons that I fail. I should probably be more aware of whats happening in my nat area and such.

As for 1v1 placement, I have 1 win and 1 loss so far. Im just really hoping not to get into bronze lol. Hmm I was not aware that you can face league players in placement matches (how exactly would that affect league ranking anyways?). However in 2v2 league, none of the matches I played on saturday had any effect on my point value. Could it be that we were facing placement teams?

Edit: Oh, the 1 loss i had in placement was against someone who was also doing placements. Im not sure about the person I beat though.

What about with zerg? How would I go about countering this Cannon block with zerg? I'm not a zerg player, but a friend of mine at work told me that he always gets beat down by the cannon block, and he can't find a way to counter it either. Well actually, he said he can, but not in a 3v3 when both his partners are idiots @.@

If you're a T player, then MAKE MARAUDERS. -_-.

In a 3n3 with idiot allies, you have lost anyway. Hence, play premade or solo.

As Zerg, scout it and spread creep. Roaches can usually deal with the turrets if they are just few, but often it is best to get speedlings and go to their base, then expand somewhere else. You'll win in minerals and can still defend your base for quite a long time with spinecrawlers. If I am not mistaken, the Protoss player cannot build the cannons in range to attack your base, and in most maps not in range of your drones either. It'll take him a while to muster troops to bring everything you've got down, especially if he has no income to speak of.

The creep extends just a little bit past the mineral line, so building along the circumference of the creep circle will allow you to kill off harvesters and base structures.

Yeah, but in a lot of maps your creep line is facing a wall in that end, and there's no space for those cannons on that side. Often he has to build the cannons to the side to try and hit drones, and if he does that you can move them to the ones further away from that edge. He can really screw up your gas, though.

Either way, I haven't had huge problems with it.

You don't need a scanner sweep to hit with tanks. You can just move to the edge of tank vision and siege there. Also, you might want to just use a fast factory build (that's what I prefer, at least).

Alternatively, lift off your CC and buildings and move to a high-yield or island.

Get marauders, its the terran's ultimate battering ram. As a zerg, get roaches, around 4 or 5 should be enough for 2 canons if you can have only one of them shooting at you. If he is trying to push inside your base, get a spine crawler or two to deny any advance.