As someone who works in, and is familiar with, Salt Lake City, I would be surprised if the Salt Lake Tribune didn’t endorse Obama.
Salt Lake City is the most left-leaning city in the state. Salt Lake has had a Democrat as mayor since 1976. Take a look at the way the congressional districts are split up. Each takes a section of Salt Lake and counterbalances it with a large rural section. Why? An attempt to make sure the Republicans outweigh the Salt Lake Democrats. Even then, Jim Matheson (D) has represented the 2nd district since 2001.
I don’t think it is particularly significant.