One in four adults has experienced online harassment, according to a poll released Wednesday.

It also said 47% of those under 35 have been victims of harassment or know someone who has been.

Allyson Kapin, the co-founder of the Rad Campaign, an online communications firm that helped organize the poll, said she has seen online misbehavior intensify over the last several years.

Women are the most common target.

"From my perception, it happens a lot more frequently than it used to," she said. "What better way to find out than to do a survey?"

The poll asked 1,007 individuals over the age of 18 about their online experiences. Of those who reported harassment, 57% were women and 43% men.

While forms of harassment varied, 44% of men and 43% of women said it was sexual in nature.

Facebook is online offenders' medium of choice, hosting 62% of the incidents. Kapin noted that two-thirds of victims knew the perpetrator beforehand.

She added there's a false perception that threats -- including to rape or murder -- are not real if they happen online.

"You can't differentiate between online versus offline," she said. "So much of that is intertwined. There is no division anymore."

The poll also found users who reported online harassment saw some results: 61% of social networks shut down the offender's account, 44% of law enforcement agencies attempted to find the offender and 35% of Internet service providers shut down offenders' email accounts.

Kapin said social networks need to spread awareness. "We cannot stand for attacks and threats," she added. "It's illegal to do in an offline environment and should be illegal in an online environment."