Styled text in note titles might add some visual clutter, but those bothered by it would be free not to use the feature. I'm afraid I don't see how it would mess up searching. I originally thought of the idea because I'm an editor, and some of my notes relate to books I'm working on. The typographic convention for book titles is to have them in italics and it subtly bugs me when a book title included in a note title is not properly italicized. Starting from there, it was a natural extension to think that other kinds of typographic styling might provide useful options for signifying some arbitrary characteristic of a particular note. Although they wouldn't address my particular little quirk regarding unitalicized book titles, I think shanecowherd's suggestion of colored tags and of using bold to indicate unread notes in shared notebooks are both worthy of consideration on their own merits.