Few things on this... No; it really doesn't have much bearing on people saving a copy; or emailing it to a friend; etc... That is why they are always resized and downsampled... if you really want a high quality print you will need to find me to get the original.
However, If one of my pictures shows up on a commercial site; or printed in a book or other commercial publication with out my permission - that's where it does have some degree of importance. It's more of an intellectual property issue; much like the difference between selling a bootleg CD recorded at a concert vs. keeping a bootleg CD you recorded at a concert for your own listening purposes... Both weren't authorized by the band, but only one will get you in trouble if you do it enough...
As far as the protection of identity... I don't post anything that I wouldn't put in a book or sell prints or posters or whatever to whomever wanted to actually buy it... so no; I really don't mind people knowing who did the work - I actually hope they do know who did the work; it would be a nice source of alternate income if people ever did think my work was worth paying for...
To get back to your question - the intended audience for anything I put on any website anywhere is everyone... That is just how the internet works, you have to accept it or avoid it.
