Used stamps exchanges.

Just a thought:

In my 300+ private exchanges I only got 1 letter missing. (aprox 0.3%)

Within this stamp exchange club 9 out of the 88 letters I sent were not registered by the recipient. (aprox. 10%).

Why is it that the "100 stamps club" letters have 30 times (!!!!) more chances to get lost than the "private exchange" ones?

I wonder...

My first 100 letters were eventually registered, even though one letter was 5 months on the way. But lately I have 4 lost letters, and two more seem not to be registered. One thought: When you send a letter to some far-away place, will it be best to try to make the letter as neutral as possible. Very common stamps on the envelope and the ID on the inside? I do not know, but I think I will try it.

Last year I received a letter from India, it was torn open, the content was gone, there was no stamp in it? Who's to blame? The Indian Post? Dutch post??
Beside this I've had some bad experiences with Italy, so far three envelops got lost (also on a private swap, or a swap through postcrossing). My point": Sometimes you just can't blame the sender / receiver

The problem is that in some countries, post is slow. I have sent some lots and still wait for more than 2 montas.

On the other hand I agreed with some members that a certain control over some users would help

I'm not sure how to improve this aspect. I will try to create some statistics to see if I can find something.
It will be difficult because I can not know if a letter is really mailed or if is received and not registered. Its one person's word against another.

I will try to find those members that are above the average.

ES-404 Poland 23 August 2016
ES-386 Russia 20 July 2016
ES-334 Netherlands 28 April 2016
ES-256 Germany 18 February 2016
ES-230 Australia 04 February 2016

ALL LOST or not registred

Should be careful with that type of statistic. Sometimes you receive a letter without id and simply cannot register.

I guess the webmaster can have statistics that show if there are members with a significantly above average rate of unregistered letters, those members should be sanctioned (send more, receive less) until the ratio gets normal.

Same here!
My latest sendings were chosen to be to Argentina/Brazil/Chile/Italy. After several months, these are either lost or not registered. After emailing, just one member had replied. Worst, the profile from the member from Chile had only one-day activity in July, after that nothing. I think the site should care more for those actively participating in exchanges, and those members not reporting activity for more than 90 days be sanctioned, perhaps their profile put on-hold.

I have also similar experiences!
I think that sanctions should be imposed for those members who do not register the letters within 45 days.
I'm sure there would be more order and honesty.

My letter lost
IT-122 26/02/2016 to Portugal
IT-134 26/02/2016 to Germany
IT-176 01/08/2017 to Brasil
IT-248 18/04/2017 to India
IT-249 18/04/2017 to Sri Lanka
IT-301 23/07/2017 to India
IT-304 25/07/2017 to Nederlands
IT-305 23/08/2017 to Australia

ALL LOST or not registred