Link to your site on your client's site

Hi all. Something that has always bothered me - developers who put a link to their site on their clients’ sites. Am wondering how others feel about that?
Was researching a web design company today, and nearly all of the sites they listed in their gallery had a “Site designed by …” link back to their own site on the bottom of every page. All of these sites were for commercial entities, so were not charities, non-profits, hobby or other general interest personal-type sites where perhaps the site’s owner isn’t paying for it.
I’m assuming that adding a link was spelled out in any agreement they may have with their clients, so isn’t a legal concern. And would hope that they are giving the client a discount for allowing the advertisement on their site.
Still, it just seems rather tacky to me to do it at all. I could see it as a copyright indication on a Legal/Terms Of Use page, or perhaps on a Contacts page as the webmaster. Or even as a meta tag for those who want to dig into the code - not sure of the implications on SEO or accessibility there! But you don’t see a communications company saying “This ad produced by us” on a client’s television commercial or magazine glossy.
Am I alone in thinking that the client’s screen real estate is theirs and theirs alone?

Good question, George. There was a big discussion about this recently in the forums:

I think that if the client has nothing against the link, it’s ok, but if the client specify that he doesn’t want a link to the develeper, the developer should remove the link becouse the client pays for what he wants to get.

Thanks Ralph. I did do a search before posting, but didn’t see this one come up. Will read through it all.

People have asked us to put a link up. Our general response is “you got paid, right?”

And what do you say to the manufacturer or you car?

When I see a site I like, I often see if there’s a link to the design house to check them out. It’s disappointing when there isn’t a link.

It’s bad enough that my car is branded by the manufacturer, but I refuse to accept a sticker or licence plate holder displaying the dealer’s name on top of it. Are they paying me to advertise their company? No, of course not - I paid them for the car. So why would I allow them to turn MY vehicle into a moving billboard? (Especially for someone who then overcharges me for an oil change! :-{)] )
Don’t forget - the average visitor has absolutely no interest in who built the site. You and I as web developers may want to know, if checking out the competition or job searching. But Joe Public only wants to know the hours and location of the store, how much for product XYZ, and why they should buy from that company.
Adding our link on a client’s site is nothing more than vanity on our part, and disrespects our client. Hide it in a metatag, or use the humans.txt mentioned in the thread in ralph.m’s post above. Then those of us who are interested will still find you, without turning your client’s site into a billboard.

Yes, that is a good alternative. Mind you, though, I don’t see the problem with putting your little stamp on a site in the footer. As you say, regular visitors won’t care, but like many businesses, putting a stamp on your work is a way to get known and find more business, and clients are usually fine with that in my experience. I don’t mind my car having a logo on it. If someone else likes the car, it’s a way for them to identify it. Likewise, those who do want a website will often mention sites they like, and it’s fair enough, in my view, for them to be able easily to identify who created it. If a builder does some work for me, I don’t mind if he leaves a little sign saying he did the work. I’m happy for him.