below the classic arguments in an internet forum of Canon vs Nikon, or PC vs Mac, it can be said that the use of watermarks on photos is well-placed. not too distant from watermarks is the way that photo-hosting social sites should do for photographers — for example: An Open Letter to Vic Gundotra and Google+ [link]. these two topics are related in terms the attitudes and goals that people have.
from long ago, it was a comment on a flickr group that I read how people would join a group and then ask that rules be changed according to their prerogative. this was insightful: flickr has it that anyone can start their own group with the rules as one sees fit, but of course, this does not satisfy the underlying need, quite possibly generalized as:
" I want to share my photos here because there is a large audience, but I want it to be comfortable to the way I think they should be shared (or things ought to be). "
— not said by anyone in particular, or literally
it is not unreasonable for people to provide feedback to sites on features, and perhaps even on the underlying behaviour possible. this takes on a greater aura by sites that depend on users to provide content, and there is something to be balanced there. however, it is always a site's decision based on their entire user-base and their assessment of users gain/lost.
the most absurd request is to prevent users from downloading a photo. well, it is the fundamental workings of the internet that the photo has to be downloaded in order for anyone to see it. these days, with bigger-is-better, sites are encouraging to upload big-sized photos. yet, the controls demanded by content-providers to popular sites can include such requests.
the consequence of this lack of control is that some people will watermark their photos. like all things internet with photography, the dials are set to "11" and watermarks can be rather intrusive when looking at a photo. this brings a backlash from photograph viewers whose enjoyments is being disturbed, or for whom watermarks signifies a misunderstanding of creative work and sharing. parallels are then drawn to many uses of art, and forum discussions get lively.
I do watermark my photos**, but not as a deterrent against people grabbing the photo and re-uploading elsewhere. my consideration is that most people are lazy and will not remove the watermark. then, the watermark is a "message in a bottle", for the rather rare chance that someone wants to look up the photo creator and then is able to track me down.
since my uploaded photos are not going to pop-up in some stream of gorgeous photographs with a sudden disturbance to the viewer of my photo with a watermark, but rather, it will be that they see a page with only my photos on display, they can easily click away if so shocked/disturbed/annoyed. alternatively, a photo print without a watermark can be ordered.
as for sites? instead of demanding so much care for one's photos, just view the internet as an ocean and the photo as a bottle tossed into it, and the watermark is the note inside. however, we can create the bottle: make it 800 pixels and use the JPG compression as severe as possible... and then it is gone forever. it is the gift to the internet.
changes to a site are a bucket of water tossed to the ocean. companies and teams that create the sites are well aware of how the internet works, how the users behave, and what draws the users to the site. the onus is on the user, and potential content-provider, to determine if the site is for them, and not to request that the site changes for their perception of fairness.
[ link ] public post on facebook to comment within facebook
** an exception is VSCO Grid, since the uploading to the Grid is directly from the app, and the extra steps of watermarking is something that is not worth doing given the controls VSCO provides against the casual image downloader: screen caps is the easy thing to do.