There's no way to know for sure if it's popular without proper research. Fanfiction popularity varies greatly. It could be that this 'godlike naruto is a shinto demigod fanfiction' has a dedicated following among those who love to see Naruto in a more divine role, especially in relation to Shinto beliefs. But it also might be relatively unknown to the majority of Naruto fans. The fanfiction landscape is vast, and many stories can go unnoticed or be a huge hit within specific circles. So, without checking fanfiction sites, reading reviews, and looking at readership numbers, we can't really say if it's popular or not.
It's difficult to determine its popularity. While the idea of Naruto as a Shinto demigod sounds interesting, popularity in the world of fanfiction can be very subjective. Some people might be really drawn to this concept and it could be popular within a niche group of Naruto fans who are into Shinto mythology and the idea of Naruto having god - like powers. However, it might not have caught on with the wider Naruto fan community. There are many factors that can influence its popularity, such as the writing quality, how well - known the author is, and how often it is promoted within the fanfiction community.