It is by now an established tradition that, at semi-regular intervals throughout the year, Valve rolls out a Steam sale, and Steam is immediately crushed by the flood of demand for cheap games. But it's not just people trying to buy stuff that causes problems. As the Steam Support Stats page shows, support requests skyrocketed to more than 315,000 the day after the sale started, more than four times the average of roughly 75,000 requests per day that Valve revealed back in early May.
The number of support requests has tapered off somewhat over subsequent days, but it remains way above the norm. Unsurprisingly, the vast majority of them are for refunds: Of the 228,722 support requests received yesterday (June 28), 205,761—that's 90 percent—were for refunds. 15,130 support requests were for account security and recovery, while 4952 people sought help with purchases and billing, and 2833 were looking for game and Steam technical support.
If that percentage has held true since the start of the sale (which is purely speculative, but not unreasonable), it would mean that Valve has received just shy of 1.5 million (and certainly more than that by now) requests for refunds since the Summer Sale began. That's a hell of a number, although obviously a very small slice of the whole Steam pie: To give it some context, we learned yesterday that 330,000 copies of Rust have been refunded, which sounds catastrophic until you realize that only represents about six percent of the game's total sales.
The good news for gamers is that despite the tremendous spike in support calls, the "typical response times" seem pretty reasonable: A refund request takes 48.72 minutes to 1.47 hours to process, while Steam and game tech support questions required 2.67 to 14.76 hours to get to.
Update: Valve confirmed that the number of refund requests indicated by the Support Stats page is accurate (as you'd expect) but did not comment on whether the percentage, and thus our extrapolated estimate, has held steady throughout the sale so far. The rep also noted that the number of refund requests "does not necessarily represent the number of issued refunds."