A top psychologist and addiction expert in the United States has highlighted the three signs that prove a person is an 'online stalker', and should seek professional help for their addiction. According to Seth Meyers, it's one thing to occasionally check the Facebook page of an ex-boyfriend or ex-girlfriend, but it's another to obsessively track someone on the web.

He says the first sign to look for is if one is spending too much time trying to get as much information as possible about the person he/she is obsessed with, and is missing deadlines or canceling social plans because of long Web-surfing sessions and-or constant monitoring of the person's social media posts.

"Spending a lot of time trying to get as much information as possible about the person," ABC News quoted Meyers, as saying.

Meyers says a person would be a 'stalker' if they are lurking on sites, leaving no trace that they were there, like a comment on a post, for example.

"Your stalking behavior is done in secret," Meyers said.

The third, he says, is if a person exhibits behaviour, characterized as a "hunt" that compelled by a deep-seated insecurity, such as visiting multiple sites to gather information, and the person keeps comparing what the person they are stalking have, and they themselves don't.

"Using multiple social media sites to get as much information as they can. The root of it is about feeling that this other person has something that you don't. You'd feel more complete if you have what they have," he said.