The Blurred Lines lawsuit from Marvin Gaye's estate has had a massive negative effect on songwriting.
Previously, everyone accepted that you had to have substantially copied an actual phrase of notes or lyrics in order to have infringed the copyright of a song. "Both songs use cowbells" wouldn't have cut it.
Marvin Gaye's estate managed to successfully argue that Blurred Lines had enough of a "feel" of the Gaye song that it was infringing copyright, without there being any actual specific phrase that was the same. Helped no doubt by the fact that the case was heard by a jury, rather than a judge.
So now songwriters are absolutely freaked out. They have to police their songwriting to make sure it doesn't have too much of the same "feel" of another song, or else Marvin's Gaye's estate has set the precedent that (in the US, at least) they can be sued.
Who knows how this ends - how do genres of music develop if songs can't sound similar to each other?