In this day and age it’s not only morally wrong to steal it’s STUPID. Eagle eyed librarians can summon up comparisons with the flick of a rhinestone crusted digit. Bloggers can sound the alarum far and wide.”
Rhinestone crusts or not, writers generally have all the same digits that librarians do, and many of the same resources. I’m coming at this from a nonfiction, “I’ve got a great idea for a book” angle, but why wouldn’t all writers perform at least a cursory check to make sure that their great idea hasn’t already been put to good use by someone else?
For me, that’s one of the first things I do when I come up with a topic or title that seems so impossibly perfect that surely — surely! — someone else has already beat me to it. A little Search Books at Amazon, a little Google Book Search, and I’ll know whether I need to come up with something else.
Granted, this would be onerous to the point of being unrealistic at the “I’ve come up with a great phrase!” level — if you come up with those more often than I do, anyway — but at least at some point in your work, how can you not do this? Where’s the payoff in not even making yourself aware of books with similar topics or titles, even if you ultimately choose to press forward with your own take on that idea?