@HM I’ve changed the title of your topic to make it more specific, so that hopefully it’s easier for people from those countries to find, and solve this mystery!
I had a look through our referrals, but couldn’t find anything special… maybe some offline media?
You can watch the box What is happening now, on the homepage. All our data input and output shows up here.
If you see something interresting happening you can click on flag username countryname or ID.
If you click on countryname and then members, you see when they signed up.
It is a nice way to learn more about Postcrossing and the members.
Edit. Homepage → Explore → Stats
is nice to view now and then, the new sign up data is for the last 30 days.