You're right in that it's essentially impossible to profit from mining YAC if you pay for your own CPUs and electricity. As BitJohn said, a good number of the remaining YAC miners are probably using systems that they neither own nor pay the electricity for (that's not to say they're all criminals 
so please don't take this the wrong way). I'd estimate -- and I have no proof to back this up, just guessing -- that the remaining YAC network hash power is split about 50/50 between people mining with GPUs and those who are mining with server farms/botnets.
To put things into perspective, I happened to be reading the forum at the moment that YAC was released. I began mining ~15-30 mins after release and within 24 hours I had 6000 coins using only a single Intel i7 3770k. Within about 5 days electricity costs began to approach the value of the coins that I was mining and I decided to halt my mining.
so please don't take this the wrong way). I'd estimate -- and I have no proof to back this up, just guessing -- that the remaining YAC network hash power is split about 50/50 between people mining with GPUs and those who are mining with server farms/botnets.To put things into perspective, I happened to be reading the forum at the moment that YAC was released. I began mining ~15-30 mins after release and within 24 hours I had 6000 coins using only a single Intel i7 3770k. Within about 5 days electricity costs began to approach the value of the coins that I was mining and I decided to halt my mining.
FWIW, I own my server farm (as made rather public on the first day or two of the coin launch), and definitely pay my own electricity. And despite being one of the few that did implement GPU mining of YAC (just not necessarily one that performs as spectacularly as people seem to think every GPU implementation is going to achieve), I still CPU-mine YAC at this point. Tons and tons of cheap Xeon-based IBM BladeCenter blade servers that people dump on eBay for pocket change just because they're a couple years old and not the latest-and-greatest blade servers on the market, reasonable power costs, and sensible and efficient design of data center cooling are key here. Per unit of CPU performance, I pay less than half what someone would pay merely for a motherboard, a bit of RAM and an i7-2600k, to achieve the same level of performance, and end up with carrier-class hot-swappable hardware, with more redundancy than you can shake a stick at, that just doesn't fail except under unusual circumstances. This was formerly IBM's hardware platform for building supercomputer clusters for NSA, who tend not to have a sense of humor about power supplies that fail when you look at them funny. This just comes down to resourcefulness and ability to scrounge the right hardware (or even to know what to look for in the first place) to keep costs down.
You can bet I would've really cleaned up had I seen the delayed YAC announcement sooner than 8 hours after the coin finally launched.. I even had the entire server cluster all prepared to network-boot a YAC-specific Debian Linux image off one of my file servers, and it was all tested and ready to go prior to the originally scheduled YAC launch date/time, I just needed the final version of the client. But alas, I was asleep (and/or in the wrong part of the world) at the time the coin finally launched.
Do you have some Ebay link of that specific hardware you use