I'm not sure what makes these socks trail-specific. Typically, I run in no-show or crew-cut socks, so perhaps the length is the reason these are considered trail socks. "The Zensah trail running socks go up to about the runners mid-shin and the superior comfort come from the fact that they are seamless in design to prevent any blistering or skin irritation. They are also thermal regulating, so your feet never get too hot or too cold. Each sock features a patented knitting technique that creates a support zone around the arch and ankle that adjusts to your foot shape to increase comfort and enhance support while trail running. Each pair of trail running socks is made in Italy to ensure the best quality."
These socks have a tight knit that would probably ward off most dust, sand, or grit on the trail, which might be the main reason to wear these for trails over roads. While Zensah makes no claims to these being compression socks, the feeling is similar, though not nearly as supportive as their compression socks. These socks have a good amount of cushioning, but not so much that my shoes felt any different. All in all they are a very comfortable, cushioned running sock that most, if not all, people would find comfortable. I used them outside in the chilly winter weather as well as on the treadmill. In all cases, even soaking wet from a muddy trail run, these socks kept my feet comfortable and I never felt like they were sagging or blister-prone. My only complaint is a personal one, in that I just don't like the length of the sock. Maybe because they feel like a compression sock or that I typically wear short socks, but the mid-shin length just felt awkward. I would suggest either lengthening them to the knee like a compression sock, or shortening them to the ankle area. Otherwise, these are a quality sock that keep your feet comfortable and protected on the trail (and on the road and on the bike as well).
(Disclaimer: I was sent this product for free to review on my blog - courtesy of Zensah. I did not pay for the item, receive payment for this review, or agree to give it a positive review. Aside from information gleaned from the company website, the opinions are my own.)