i lost a game yesterday and i see my opponent labelled as "slightly favored" but when i check the fella out, it's a platinum league player.

@evo , whats MMR?

can we check the MMR?
or it's hidden?

Points

Your number of points is what decides your place in your division. After having completed your placement matches, you start out with 0 points[4]. These points only decide your place within your division, and there is a hidden "Matchmaking Rating" (MMR) as well, which decides which opponents you will face. Since there are no global or regional rankings, the displayed score isn't an accurate measure of skill[5] when compared to anyone else. This is because the visible rating does not match the hidden MMR rating, and is influenced by the Bonus Pool. Each play-season the visible rating will be reset, while the MMR rating stays intact. This makes it even harder to derive the true skill of the player.[6]

Earning and Losing Points
You earn or lose points by winning or losing matches, respectively. To simplify how it works in practice[7]:

y = (+/-)12 + x + z

where

"y" : the total number of points
"x" : the relative expected skill level between opponents (weighted difference in MMR which can be negative)
"z" : the points you get from your bonus pool
=> "x" is a value in the interval of [-10,10], positive numbers are when your opponent is favored

if the game says you are even, "x" is part of {0,1}
if it says your opponent is slightly favored, then "x" is part of {2,3}
if it says your opponent is favored, then "x" is part of {4,5,6,7,8,9,10}
(of course, if you are the slightly/favored player, then "x" is negative, which means you will lose more than 12 points)

"z" will be be greater than zero when

your bonus pool is >0
you are victorious
If these 2 conditions are met, then Z will be equal to 12+x, permitted you have enough points in your bonus pool.

Bonus Pool
The bonus pool is the sum of all "bonus points" you can get, which are added to the rating points you earn after a victory. They are there to give the player a catch-up boost if they haven't played in a while, in other words, they serve as a means to keep up with the inflation of points in the league.

Your bonus pool seem to not be reset once you move up (or down) a league, as your initial rating in that league should reflect your calculated rating at that point in time.

Hidden "Matchmaking Rating" (MMR)
In addition to your points, there is also a hidden Matchmaking Rating, presumed to be very much like the WoW Arena Matchmaking System. This rating decides which opponents you will meet, and tries to quantify your skill level. It (presumably) takes into consideration when you have winning streaks or losing streaks. Moreover, it is this MMR that decides if you're eligible for a promotion or a demotion. The aim for the MMR is to rank you in such a way that you have ~50% win rating. You presumably start out at 0 and then your MMR climbs to the level of the people against which you win roughly 50% of the time.[8]

Sauce : http://wiki.teamliquid.net/starcraft2/Battle.net_Leagues

yes I just asked uncle google.

I just don't fully understand the formulas, why pick 12? and why is it -/+ 12? if you lose, you lose 12 points?

Do you get to see how many points you have?

I just bought the game and did not skip the practice league, I still have 14 games left to play before I enter the placement matches so I don't know what it's like after practice league yet.

Congrats bro..I got promoted from silver to gold to plat too these last week

About 3-4 weeks i think. I play more 2 v 2's and 3 v 3's though, as my friends play as well

I notice some of the top bronze/silvers playing like a plat. Their macro definitely on par with a plat. Only thing they dunno is timing pushes. Dang.. if I didn't know better, I would've lost to all these players >_<

Just reached high enough to start meeting zerg players that go for roaches.
Having a hard time now.

That 5-6 roaches poking at the front of my base when I only have like 3-4 stalkers is quite tough to handle...

@Aeco

That's so true. They lack confidence sometimes. Just like me. I've rested my 1v1 since last month at silver. Now i've hit plats in 4v4 and 3v3, I'm going into 1v1 again, much more confidence.

I think confidence plays a big role in teaching you when to do pushes. Sometimes I keep thinking that the enemy is hiding a tonne of forces in his base, so I can't push in. After losing and watching the replay, I realised he had only 2 stalkers and 2 cannons left... and I had a 50 food army.

@SiewKaiz

Yup. Especially when stalkers are defending behind buildings with a better range than roaches.