But some of this clever guys (I don't know who exactly), was able to modify original mmc code to make it impossible (now) mine mmc with GPU.
The coding for MMC2 was not changed. If I remember my early months of 2014 correctly, the Radeon HD 7970 or Radeon R9 280X produced ~20HPM at around 350W. The i7-4770K initially produced ~3HPM at less than 90W. When yvg1900 released YAM, the i7-4770K jumped to ~13HPM. GPU miners simply could not compete with the power efficiency of CPU miners when they are between 2 and 3 times more efficient. AES-NI FTW!!! On a similar note, it is normal to see a dual socket Xeon servers pushing 40 HPM when using YAM. The problem right now is that all the default pools are down and YAM stops mining when it is unable to submit shares for the developer.
Code was changed. This is a fact.
Exactly after that all major pools (mmcpool.com and 1gh.com) delisted mmc.
And people lost interest to mmc, because ask yourself - how many people has Xeon servers?
Also, yam-miner main problem is a proprietary closed-source code with hardcoded (dead now) pools.
Seems pump-and-dump attempt.

More interesting thing is a 170K mmc wall at 3600...
I don't see the wall on Polo - maybe it's already gone.
When you say "wall", you mean that, at 3,600, 170K of MMC will be sold thus pushing down the price, correct?
Is it possible to have a "fake wall" if one does not own 170K of the MMC?
Somebody set sell order of 170K mmc at 0.00003600 BTC. Now it's 66K mmc at 0.0003700
And no, you can't set a "fake wall", because you have to hold the coins in your exchange wallet to trade them.
So when you say the 170 MMC sell wall is "interesting" it was "interesting" because...?
Forgive my naivety but I'm just trying to understand.
Understand what?
Is this the same coin that Freetrade developed some years a go?
Yes.
But some of this clever guys (I don't know who exactly), was able to modify original mmc code to make it impossible (now) mine mmc with GPU.
Delinquency did that and I still think it's brilliant. By the way, Memorycoin was originally designed to be GPU/ASIC resistant but it simply failed in that part.
GPUs along with botnets hit this coin badly and made it depreciated. Therefore, FreeTrade abandoned, Delinquency took over and designed the coin impossible to be mined by GPUs/ASICs.
As the coin supply is reduced dramatically couple of months ago (again based on original design), all the coins in the market should have high intrinsic value. In other words, you have a great chance to resurrect the coin now as the base is stable and you guys can make a difference and make it appreciated.
Yes, but this supply reduction, GPU mining impossibility and CPU mining difficulty leaded to nearly death of mmc

Solo mining possible only on low difficulty. If it raises to 0.00000010, for example, it will be impossible and not economically viable to people to mine mmc.
So, why new people should be interested in mmc?