My mother always said that politics was not good dinner table conversations. Well, it turns out, it isn’t proper online fodder either.

A new report out by the Pew Internet and American Life Project finds that about 18 percent of people who use social media sites have blocked, unfriended or hid someone based political posts.

It’s been suggested that social networks act like echo chambers of like-minded friends; birds of a feather and all of that. Interestingly however, only about a quarter of users always or mostly agreed with the political content posted by their friends.

So what kind of comments will shrink your social circle? If you post about political subjects frequently, if you’re argumentative or your online rants are just downright offensive, you stand a good chance of getting unfriended. But, take heart, the folks most likely to delete you are generally acquaintances or a distant friend. Close friends will probably just ignore your politically charged updates. According to Pew, two-thirds of social networking users will simply give your tweets or status updates the cold shoulder.

All this isn’t to say that social networking sites can’t generate a lot of political buzz—especially during the campaign season. According to the study about 47 percent of users have “liked” a friends political commentary and 16 percent have friended or followed someone based on similar political views.