I have looked at, and written about, the "miles for reviews" option on Gezi.com and it's pretty straightforward:
- You can actually earn vast amounts of miles per review, as you get (give or take) an extra 50 miles per photo.
- The above said, and as noted above, you are limited to 10,000 miles in any one year.
- You can currently only earn Turkish Airlines' Miles& Smiles miles, but they have plans to add additional programmes.
So, not least with the demise of holidaycheck.co.uk it's a decent, if somewhat limited, way to earn an extra wedge of miles. Miles&Smiles might not be familiar to everyone, but it's actually a pretty good FFP once you're comfortable with it.