"We're in a climate where it's easy to accuse a company of spying on you by various means with a distinct possibility that you could be right, but sometimes a reality check is needed. A Reddit user recently posted a thread accusing Valve of writing code for VAC that iterates your DNS cache and sends the hashed entries to their server. The proof provided of this was a prettied disassembly (that was not easily reproducible due to how VAC loads symbols) that showed only that VAC was indeed iterating the DNS cache, which any knowledgeable programmer understands is not exactly an uncommon thing to do, as no socket code was to be seen. Today, Gabe Newell responded to these allegations by confirming that no they do not in fact snoop your cache entries.
There are probably a few things to learn from this, including not trusting a screenshot of code that looks complex without actually understanding what it's doing. A lack of any level-headed investigation is a bad idea and it's important to handle these situations before they snowball into a mob (as Redditors are bound to do)."
Steam practically prints money for Valve. There would be little to no incentive for them to data mine their users DNS caches. I'm not saying that Valve is incapable of doing evil, but if they were going to, it would be by doing something far more profitable than this.
As a disclaimer, I am a huge Valve fan that spends hundreds of dollars on Steam games annually. So yeah, there could be some personal bias.
FalleStar makes a valid point. You may not agree, but this post isn't flamebait.
"Steam practically prints money for Valve."
And why do you think this is so? Games? Of course, but that doesn't mean that they couldn't also be gathering data to be shared for even greater profit. In this day and age, it would be foolish to think they wouldn't be doing this--corporation after corporation is being shown to have hands deep in NSA data gathering, and trust me--they are NOT doing it for free. It's a bit of a straw-man argument to claim that someone wouldn't try and make more money just because they are already wealthy.
Greed is a disease, never satiated.
Perhaps it would be foolish to do so in your opinion, but I trust Valve. It's a matter of trust as Gabe said in his release. Valve has a reputation of being pro-gamer, and I trust that it was done is for this specific anti-cheating policy. Why do I trust Valve? Because hats.