This is the technique they used which influenced previous theories to skew more towards a wetter surface:

Now, new isotopic measurements by NASA researchers reveal that an ocean once covered approximately twenty percent of the Martian surface. This new picture of early Mars is considerably wetter than many previous estimates, raising the odds for the ancient habitability of the Red Planet.

What do you think?  Also here is a very interesting comment:

They have taken photos of what may look like glaciers. That is fascinating to me if true. It would have had to have snowed a lot and for a long time for glaciers to form. With just a few tweaks, Mars could have been another earth and full of life.

It is definitely a possibility.