When voting for the Community Choice Flash Sale, I got this notification.     Once you reach Steam Level 5, you'll get a card every 3rd time you vote for the Community's Choice Flash Sale and you'll be granted the cards for your previous votes.   Can someone explain what these "cards" are and what it means by "you'll be granted the cards for your previous votes."?
Is it purely a 'gotta-have-them-all' mindset, or do they actually serve some purpose?  I notice that you are able to sell them on a community market. For a test I listed one, and someone bought it for 50p. Not exactly a huge amount, but I don't understand why someone would spend real money on them.  Am I missing something?   Are they redeemable for games or money off vouchers or something 'tangible' that I'm missing?
Why does WMI Provider Host (WmiPrvSE.exe) keep spiking my CPU? I generally keep my laptop on 24x7, and at the end of the day it's really annoying to have my thighs burnt because over overheating.   The overheating seems to be a result of WMI Provider Host (WmiPrvSE.exe) spiking the CPU utilization to 25% every few minutes.  Why does this happen?  I have an HP Envy 14 (with the HP bundled crap) running on Windows 7 Home Premium.  (Note: Based on @nhinkle's , it seems that HP Wireless Manager might be the culprit, is there any way to confirm this?)     This question was a .   Read the Feb 28, 2011  for more details or  Question of the Week. Is there a reason why we gain ghost reputation on the meta of an SE website? Is there any reason behind the ghost reputation we gain on the meta of a Stack Exchange site? This reputation doesn't add up to anything, but it still shows me I have gained some. Is this supposed to make any sense? I am on Ubuntu and I have forgotten the password for my Gnome Keyring (yes, stupid me, I know). Any way I can get it back? I have already looked at , but it says it's not possible if my home directory is encrypted and unfortunately my home directory is encrypted. 3-regular graphs with no bridges Problem. Use Tutte's 1-factor theorem to prove that every 3-regular graph with no bridges has a 1-factor.  I honestly have no idea how to approach this problem. I have drawn a couple of graphs to gain some insight to no avail. Any hints or tips will be greatly appreciated. I am superimposing CGI over video footage, and have run into a problem in making materials for objects that act as 'shadow catchers'.  Essentially I want a shader that is shadeless—like an emitter—but catches shadows and light from other objects. This is so I can reconstruct objects in footage so other objects in the scene interact convincingly with them.  Here's an overcomplicated diagram to illustrate my point:   (In this particular scenario, the problem could be glossed over by using RGB curves, but that is definitely not the case with more complicated scenes)  Isn't this a common situation? How to the real guys do it? Thank you.  (I am welcome suggestions of other ways of doing this.) .NET DateTime.Now returns incorrect time when time zone is changed Moving here does not mean moving to a new city or something like that. I am talking about the people that just can't stay at one place. It is impossible for them to sit put at one place and relax. The following will cause infinite recursion on the == operator overload method      Foo foo1 = null;     Foo foo2 = new Foo();     Assert.IsFalse(foo1 == foo2);      public static bool operator ==(Foo foo1, Foo foo2) {         if (foo1 == null) return foo2 == null;         return foo1.Equals(foo2);     }   How do I check for nulls? Differentiation - simple case Is the force which throws a body on a rotating disk outwards centrifugal force? If some object is kept in a radial groove made on a disk and the disk is rotated with say constant angular velocity.   Now as we know that the object moves outwards ie away from the centre of the disk. I want to know which force is it which throws the object outwards.   As centrifugal force is a pseudo force and hence when the observer is in ground frame it shouldn't be present so which force exactly pulls it out. Rich Wizards, Poor Muggles Extended sound of thunder I guess I can live with the fact that the  changes size drastically when he transforms, but why does his shirt rip off and not his pants?  I think that we need a little better answer than "it keeps us tied to the fact that inside he's still human". Automatically make or update a copy real-time on another hard drive volume whenever files are saved to a particular folder How to compute $k$'th roots $\!\bmod n$? I have the following equation: $$ n \equiv M^k\mod(b) $$ where n, a, b are integers, and M is unknown. How do I solve this equation to find the M value? Those a and b are public keys of the RSA algorithm and n is the result of encryption. I need to find the encrypted message. Why only light nuclei are able to undergo nuclear fusion not heavy nuclei? Is it because of the binding energy or the binding energy per nuclei .  I am having trouble with this whole binding energy and nuclear fusion concept. How do I run a 'sudo' command inside a script? How do you performance test JavaScript code? How can I "grep" patterns across multiple lines? It seems I am misusing grep/egrep.   I was trying to search for strings in multiple line and could not find a match while I know that what I'm looking for should match. Originally I thought that my regexes were wrong but I eventually read that these tools operate per line (also my regexes were so trivial it could not be the issue).  So which tool would one use to search patterns across multiple lines? How is it, that $\sqrt{x^2}$ is not $ x$, but $|x|$? As far as I see, $\sqrt{x^2}$ is not $x$, but $|x|$, meaning the "absolute". I totally get this, because $x^2$ is positive, if $x$ is negative, so $\sqrt{y}$, whether $y = 10^2$ or $y = -10^2$: $y$ is positive.  But then I remember that $\sqrt(x)$ is the same as $x^{1/2}$ and thus, $\sqrt{x^2}$ is the same as $x^{1}$.   So, as far as I get it, $\sqrt{x^2} = x^{2/2}$.  But then, I can cancel $\frac{2}{2}$ to $1$. So: $\sqrt{x^2} = x^1 = x$.  Where does the absolute value in this derivation of the calculation come from?  I get it why its there: Because $(-x)^2 = x^2$, so the radicand is always positive. But from $\sqrt{x^n} = x^{n/2}$ I dont understand how it gets there.