The prevalence of soft (bit flip) errors is likely significantly higher than it was in 2009, or even 2012. In Flipping Bits in Memory Without Accessing Them: An Experimental Study of DRAM Disturbance Errors (covering the “row hammer” issue), which tested modules from a few different years, the error rate picked up significantly starting 2013, likely due to increasing density in the manufacturing of memory.
The paper uses pathological access patterns (still, only reads) to trigger errors on purpose, but there are legitimate things software might do similarly and trigger the error. Can’t be too specific, but I’ve seen these errors in production, and it’s only because we had ECC ram that we were even able to tell that the strange behavior was due to a memory error – I also think that being able to tell that memory errors are happening is much more valuable than any of the reliability benefits.
Also turns out to be a security issue: http://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html