In the description, it mentioned the use of polarizer to stop reflections. From what? how would it probably look like should a polarizer wasn't in place?
How do you know WHEN to do it? Hold it up in front of your eye and rotate it and see what happens. In general, polarizing will increase color saturation regardless of other considerations. Degree of polarization depends on the angle of the light; maximum polarization is achieved where the light source is at right angles to the lens.
With extreme wide angle, shooting landscapes, polarization can be a problem; my 10-22mm lens covers over 100 degrees at 10mm, so I can be shooting witht he sun well off to one side and see zones of polarization in the sky, witht he sky darkest in the center of the picture, lighter at both sides, and mightest on the side closest to the sun.
It's easy to over-polarize skies, especially at high altitudes, so they look unnaturally dark. You can see the results through the viewfinder though, so it's avoidable.
Ploarizers work very well in removing surface reflections from water so it looks transparent, or more trasnparent. This is why fisherman wear poalrized sunglasses. In fact, on the picture you posted, it may be that there were secondary reflections on the water drops that have been polarized out.
It's "safe" to use a polarizer on all outdoor shots, in the sense that you can always set it to a neutral position where it polarizes nothing, basically, or anywhere in between, so yeah. But you lose a stop-and-a-half of exposure, even two stops, and you add another glass element to the equation, so I don't leave it on as a matter of course; I just mount it when experience tells me it will be beneficial.
But a polarizer can actually function as a "neutral density" filter if you're trying to eke out a longer exposure time, like in the 2 second challenge, if 2 seconds at f/32 is still overexposed; the polarizer will help you there.
When Bear takes photos with his 10-22mm I doubt he uses a polarizer. Instead he uses a gradient filter in PS right Bear? A polarizer using a 10-22mm would create a vignette at the widest angle ;)
The Ghost Yachts shot is polarized. Not so much for the sky, as because there were reflections on the white vinyl I needed to get rid of. The other two are not polarized. The bottom one has a blue-to-transparent gradient laid in on the sky, not a variable ND filter. I see no need for those when i can customize it in PS very easily.
Rikki, I have an ultra-thin polarizer for the 10-22 and it does not vignette at 10mm, but I rarely use it because of the uneven skies that result. Of course, they are uneven anyway, but the polarizer exaggerates the effect. I have it in the bag for intensifying colors in the foreground on shots with little or no sky, mostly. I don't use it very often. It's a Hoya, and it's very expensive; 172 bucks at B&H :-(