Given recent discussions - decided to pick up the mantle. Please feel free to post any stamp that you see online that raises suspicion as to authenticity etc.
The 'review' page of stampsmarter does the same thing. As that has not been used very often, I will leave it to Don to suggest ways to reconcile & we can all come up with an appropriate solution that will allow the broad base of knowledge here to be used to its fullest.
I will start us off - again, with inspiration from a recent post. Many others have commented on the large amount of problem listings on hipstamp - which I agree with. This is just the latest example, although an egregious one:
https://www.hipstamp.com/listing/tu...019/12292216
Worse - the guy claims to have 2 of them!
https://www.hipstamp.com/listing/tu...017/12292317
The seller claims both of these are Michel #741H. That translates to Turkey in Asia Scott #28A, or Isfila #1010. This is a $1750 stamp, whether mint or used. The reason for the high value is that the number of copies that got a 'handstamped' overprint is just 130. They are extraordinarily rare. The fact that the seller is only asking for $333 for these is further evidence of lack of knowledge. When these authentic stamps do come up for sale, they go for nearly close to CV.
These stamps are actually Turkey in Asia Scott #56, or Isfila #1041. A stamp with a CV of $12 mint & $6 used. Very common. These stamps have typographed overprints - NOT handstamps. The difference between the two is easy to see, once you've seen an actual handstamp.
For those that are curious, and want to compare to the above overprints, these are 2 examples of handstamps:

