Apparently, it was that a pro colleague of his, named EFINK, wanted to send a message of appreciation:

Also, I saw your work, “Miao Diary”. I read it all the way to the last page. It’s so interesting! I was really impressed to see that people other than the Japanese were drawing Nekomimi. I think it takes a special sense to like Nekomimi, and it seems that the height of its popularity in Japan has already passed. However, I think Nekomimi is well recognized as one of the lovely ones. To see that it is also recognized in foreign countries is wonderful.

Needless to say, to be recognized by a professional like EFINK is a great honor for me. I’m even more impressed that he persisted in trying to show his appreciation for my linking to his site, even if it took him a year. That must be the Japanese sense of honor.

Go, Sixten! And I knew from the start that Miao Diary would go on to better things than simply mocking Miao.

BTW, I'm glad that common people (e.g. non-programmers) still use e-mail, although I noticed that in only two recent years the e-mail traffic by commenters of Ani-nouto pretty much petered out, in particular from new people. In part it's the general decline of the blog, certainly, but perhaps a shift in communication patterns played a part too.