Originally Posted by
FBinNY
It all depends where the crack is, and what caused it.
Some can be ridden forever without any repair, some will grow, but can be salvaged, and some are clear and present dangers and the frame should be given to the scrap man.
I'd also add that there's no real way to tell which of those descriptions your crack fits just from looking at that picture, maybe cross-post this in the framebuilders' section of the site and someone will know how to determine which it is.