According to Pew’s most recent study on social networking sites, most users don’t agree with their friends’ political postings. As the election approaches, it’s only going to get worse. Here’s why we’re unfriending one another these days:

View Photo Gallery: In seven years, the social networking site has grown from a project hatched in a college dorm to the largest social networking site in the world, well on its way to hitting its goal of having 1 billion users.

• Because you post too often about political subjects (10 percent of users have blocked or hidden someone for this reason)

• Because you posted something you find so disagreeable it was offensive (9 percent)

• Because you argued with me about politics (8 percent — but doesn’t it take two to make an argument?)

• Because you posted something that would offend my friends (5 percent)

• Because I disagree with your political posts (4 percent)

Users are also often surprised to learn that their friends’ political beliefs aren’t the same as theirs: 38 percent of respondents in the survey said that they discovered through a friend’s posts that his or her political affiliation was different than they’d assumed.

Unfriending has become so rampant that the word was 2009’s word of the year in the Oxford Dictionary. Emotions run high around unfriending, too — especially now that there are apps that notify users when they’ve been dropped from someone else’s Facebook list. There have even been cases of people reacting violently in real life to a cyber unfriending.

Other studies about Facebook unfriending, such as a 2010 one conducted by the University of Colorado at Denver, have come to similar conclusions.

“Unfriending reflects the instrumentalization and commodifying of friendship on Facebook,” Lee Siegel, author of “Against the Machine: Being Human in the Age of the Electronic Mob,” told the New York Times. “Why unfriend someone at all? After all, in the real world, you don’t just ignore an obnoxious relative. The very act of unfriending acknowledges that the Facebook definition of friend is different from the traditional.”

So, if you want to hang on to your Facebook friends as the election progresses, keep it civil, and make generous use of your newsfeed settings.