A blog would be a good choice. I've been around woodworking forums a lot of years, and can't remember a spear gun build. It would be cool to see the process used, and a blog leaves plenty of room to illuminate a subject. Plus if it goes as some good blogs do, it offers plenty of room for opinions about what folks are seeing. Sometimes they even tend to guide the build some, especially if the builder gets stuck on a part. 

I look at them as sometimes educational. like when a really good builder like Paul, or Dennis are doing something involved, you can just sit back and go Ooooooooohhhhh, or other smart comments similar to that.

Sometimes they are community helpful, where questions are answered, and answers are questioned, within reason anyhow.