I learned about this thing a while ago (about 4-5 years ago), when it was quite common in the US, and I thought it would be difficult to implement in Japan due to infrastructure and environmental constraints. However, it seems to be gradually gaining traction in Japan, so I started buying a few necessary items from overseas last month for research and experimentation. Since the Senkaku Islands dispute was in full swing, when I tried to buy something from China via email, I was met with a "We sell worldwide EXCEPT Japan" response, which caused quite a bit of trouble.
So, I ordered some of my main items from overseas in early October from Taipei, and I paid via PayPal right away. However, no matter how much I waited or how many emails I sent, I received no response. I repeatedly called the sales company's offices in Shenzhen, Hong Kong, Taiwan, and Tokyo (the Tokyo office seems to be a virtual office), but no one answered. I finally managed to get through to the Taiwan office, but the person on the other end didn't understand English, and I don't understand Chinese. Fortunately, I was able to get through to someone who spoke a little Japanese, and I immediately emailed them asking for an update on the situation, but I received no response whatsoever.
I was half resigned to the fact that I'd been scammed. While researching PayPal's Customer Protection Plan, I decided to try contacting the Japanese authorities, and was about to call 110 when I decided to call the Tokyo office one last time. "Hello?"... It connected! And in Japanese! In reality, the call had been forwarded to Taipei (strictly speaking, it wasn't a forwarding), and it seemed that a Japanese person in charge in Taipei had answered. I rattled off the details of what had happened and the blunders in Japanese—or rather, in Kansai dialect, which I can't speak in English—and demanded an immediate resolution.
And just a little while ago, three days later, the product finally arrived. I'm so relieved. There were a lot of things that worried me, but the seller's response afterwards was quick and sincere, so I guess it's all good.
I've been doing these kinds of overseas trades for a long time, so I'm used to it, but there's always a bit of anxiety about whether the goods will actually arrive. I've had several close calls in the past, but so far, I've never paid for a product and not received it. I pursue the matter to the very end and try every trick in the book to get them to show me some sincerity. This time, the other party was in China instead of the US, so it was a little different, and I almost gave up, thinking I was going to be scammed, but somehow it all worked out.
...I've written at length about the situation, but as for what the important thing is... I'll write about that little by little from now on.
It depends on the person, but it's incredibly convenient, incredibly economical, and fun. When I learned about it in America, I was amazed that ordinary households had something so useful. Actually, there's a hint in the text above.