You're as subtle as the brick in the small of my back

Obviously, a lot of bands have connections with each other. It could be something as simple as similar music, or the same singers for both bands, or something as heated as a bad history with a lyric rivalry. Want some examples?

Paramore/Renfue
--Comparitively, Paramore is pretty well-known. Renfue is not. Most people have never heard of Renfue. I ran into Renfue accidently: I was downloading some new Paramore stuff, clicked on a song later, and it wasn't the song it was labeled as. To be honest, I still thought it was Paramore, I just thought it was another unreleased song. The music, as well as this singer's voice, sounds similar to Paramore. I listened to it a couple of times and realized it wasn't Hayley Williams singing—so I googled the lyrics, youtubed the song, and found this huge thing that was going on. Apparently people on YouTube are getting pretty worked up about the fact that Renfue's music is getting labeled as Paramore's in the illegal downloading world. So watch out, if theres a tag that says Paramore, double check it.

Flyleaf/Fireflight
--I've been a Flyleaf fan for about a year now. They're definitely labeled as alt/metal rock, and they get pretty hardcore. Lacey, the singer, absolutely screams her lungs out in a lot of the songs. It took me a little while(when they released their new album out this past fall) to realize that they're also a little bit Christian rock, which I never would have expected. It's subtle, and not all of it is like that—either way, it's pretty good, and the lyrics are just plain good. A few months ago, my laptop crashed, because of downloading of course, so I switched to using Pandora for a while, and a band called Fireflight popped up. They're not quite as hardcore as Flyleaf, but definitely on the same level, and they are also Christian rock. What I like about these bands is that they don't throw religious views in your face with their music. They HAVE views, but sometimes they're hard to catch, because the music is just good.

Taking Back Sunday/Brand New
--Listeners of TBS and Brand New know that a feud existed between the bands for a long time. The best way to explain it is to copy and paste off of wikianswers:
The Long Island Rock legend goes that once upon a time, Jesse Lacey, now the lead singer of Brand New, was best friends with John Nolan, former guitarist/singer of Taking Back Sunday and current guitarist/singer for Straylight Run. As the legend goes, at some point during the duration of the close friendship, Jesse's girlfriend cheated on him with John. During their fight, Jesse allegedly said "You're as subtle as a brick in the small of my back so let's end this call and end this conversation." However, this is ironically close to the line in "Seventy Times Seven." This song was released on Brand New's first album, Your Favorite Weapon, originally released October 9, 2001.
While TBS was writing songs for their first album, Tell All Your Friends, originally released March 26, 2002, John Nolan heard the lyrics to "Seventy Times Seven." In response, TBS wrote the song "There's No 'I' in Team." Some speculate that the song was an apology of sorts to Jesse. Some say it was an explanation. But it seems that the best explanation is that it was TBS's way of giving the lyrical finger to Jesse. Lyrics such as "Wearing your black eye like a badge of honor/soaking in sympathy" and, most notably, in an interlude that also includes the lyrics "Is that what you call tact/You're about as subtle as a brick in the small of my back/so let's end this call and end this conversation/That's right he said it," seem to support this last explanation.