I have been using Lightroom for about 3 yrs now. I use a MAX of 40 sharpening on my pictures with a radius of 1. A lot of time I don't sharpen them at all, or very little. The noise you are seeing in Flickr and other places is most likely from the compression of the images as they are loaded. Are you using the plug-in inside Lightroom to upload to Flickr? If the pictures are going to be viewed online I always check the sharpen box in the export module and then select "screen" and "standard" for the sharpening settings. When uploading pictures for online viewing, you also want to make sure you get the appropriate pixel dimensions as this can make a big difference. Another reason for seeing a lot of noise is over-sharpening. Try backing off a little and see if the noise goes away.