Ranked in these QuestionsQuestion Ranking
Pro Social experience
StampWorld lists events, and also hosts forums, clubs, and organizations through its website. If you want to, you can meet up with like-minded people easily.
Pro Massive catalog
The stamp catalog is massive. It lists not only countries, but also provinces within countries to easily find the stamps you're looking for. Altogether, there are 750,000+ stamps listed.
Pro Built-in marketplace
You can browse for new stamps, or sell old stamps easily through the website. There are also dedicated spaces for auctions and dealers.