Will, thanks for the comment. Yes, in theory, I could possibly have pursued infringement in cases where every detail of my shot was duplicated. In reality, though, it is so expensive to take legal action and so unlikely that the court would find in my favor that the law becomes somewhat meaningless. In the case of copied text, where several lines and paragraphs were copied word for word, I always take legal action.
Incidentally, a few months ago I did an exchange with the editor of a local magazine. I did a session and provided prints of her kids in exchange for a print ad. Since I don't do any print advertising and really hate busy, obnoxious ads, I brainstormed some ideas for very simple taglines to go with the image I chose to use. I ended up using "Life, exposed." Not terribly cheesy, fairly functional.
Last week I got an e-mail (friendly wording, but with a bite to it) from a photographer in Boulder informing me that I can't use her trademarked tagline, and that I need to come up with my own original phrase rather than copying hers. Quite a shock to me! I don't know any photographers in my area, and don't have any idea what any of them uses for marketing or whatnot.
In my note back to her, I assured her that the overlap was completely coincidental. I'm the sort of person who makes a point out of being unique and distinct. Although she thought her tagline was very unique, in reality it's just two words that are used A LOT in portrait photography, put together. When it's two words in question, coincidences are absolutely possible, even likely. When we're talking complete paragraphs (and I mean, one girl used my bio word for word, including my date of birth!) it's an entirely different story.
Anyway, sorry for the hijacking....