As a professional photographer who sells images via my website, embedding watermarks is absolutely essential. Early on in the piece, I placed inobtrusive watermarks at the bottom of my images only to find them cropped and placed on numerous websites and blogs. While I do not have a problem with blogs per se, I do have a problem with folk lifting my images for commercial use and/or passing off. If you think that low resolution will stop theft, you are sadly mistaken I'm afraid! Through TinEye, I found that one of my images (low res and watermarked) was lifted, cropped and was appearing on a book cover. That is not unusual by any means. Eventually the publisher paid up (including damages).
Regarding blogs, through TinEye, I have found 39 Islamic blogs publishing an image of a young woman dressed in a hijab. As I said, I don't have a real problem with blogs as in my opinion, 99% are not commercial use. But I draw the line at commercial use of my work. There is also a Hungarian website which has 40 of my images on their site which they are selling as postcards
These images are not watermarked because I did not watermark at the time I uploaded them. I am in the process of instigating a DMCA takedown notice on their server.
I don't like watermarking my work but I really need to stop theft, or at least deter those who think that everything on the Net is free for the taking.
Sheila