I thought this was probably already posted, but didn't know how to phrase it in order to search it. I was hoping the automatic duplicate search would turn up something, but nothing came up on the topic. So here goes:
Some freelance web designers often "sign" a design or otherwise indicate authorship on them (I'll use the term "to sign" for that action, so we are clear). Not only does it entice future business, but it serves the main purpose of providing a simple way for a viewer to identify the designer should they wish to do so.
A popular form of identification is probably adding a note to the footer, such as "Made by Jon Allard" or "A design by Foobar Productions" with a link. I have also thought of including an HTML comment in the source code.
Now those means are sure useful for the designer and the soon-to-be new client, but the impact of those means on the brand being represented on the website is real. There might be some perceived lack of professionalism in those notices, both on the part of the client/website and the freelancer/designers.
Is there an commonly accepted practice on that regard, and if not, what is a viable way of indicating authorship of a web design without significantly hurting the client or freelancer's brands?