Oh great, so we can't even watermark our photos for use online anymore?
I suppose that has been an issue for a while anyway, skilled photoshopers knock out the watermarks all the time. Never upload in printable resolution is the trick.
I've used a number of different noise reduction software and one thing that is common is that with synthetically generated noise, they work really well. It's a repeating pattern and can target those bits easily. An image captured from a sensor is not a repeating pattern of noise, it's all ever so slightly different. In the past I have found that NR is needed on a case by case basis, and Neat Image, Noise Ninja, Topaz and Adobe's own Camera RAW all seem to have their own quirks that do a better job than another on a particular image - this takes too much time to use them all and compare case by case.
Is the image for screen or print? If it's for print, we can get away with a lot more noise than on screen, even to the point where some prints look better with a little added noise, it seems to make them sharper on paper.