In Mr. Ferris' own words: “There is no identifiable characteristic of a dark slope streak that can definitively say whether it was formed by water-related processes or not."

I think that statement says it all. What we have is a very speculative AGU conference poster presentation that has probably gotten more atention than it deserves - in part because the "authors" themselves issued their own independent news release about it. Its an interesting idea, but even Mr. Ferris admits that there are many other plausible explanations for these streaks.

I suspect that Mr. Edgett is correct, but we shall see.