Hi, Jo here. I've been thinking about book covers a lot recently, for a range of reasons. Covers are important, because they do affect our purchasing of books, but also sometimes our relationship with a book. The cover can form part of our expectation, and continue to influence us as we read. Of course with e-books covers can have less influence as generally once we start to read we'll never see the cover again.
But let's think of dramatic examples. I love Terry Pratchett's work, and I'm sure it would always have found its huge readership, but would it have become popular so quickly without the brilliant cartoonish covers?
Typepad is doing odd things with images, which is a shame when I'm doing an image-based blog. Onward! With apologies.
To look at historical romance, there was a time a while back when covers for humorous ones had a cartoony or cut paper cover, which was very effective at telling readers what to expect, especially as most of us like humor. I'm not sure why they didn't last long.
The look continues in Britain, especially for Julian Quinn, who of course often includes light humor in her books.