zomg http://www.wakachan.net/ is down.
The major problem with a centralized navigation frame is that if the server where the nav is located is down, one cannot access the rest of the hub.

go here, you zealot:
http://www.teamtao.com/neko/

You could always save a local copy periodically, or just bookmark the boards you frequent.

I fall back to http://ashitaka-san.home.comcast.net/wakachan/nav.html when there is a problem.
And now I have one more nav http://4-ch.net/
Failing all that, I look into my bookmarks - but that is tedious as I have many.
Yeah, I should keep a copy of the various nav html too.
Still, there are boards not listed anywhere, like http://wakaba.c3.cx/sup/index.html
Maybe I should write my own nav.