Facebook is still the giant of social networking, but a significant slice of teenagers report "Facebook fatigue" that's driving them away from the site as their friends move on or their parents encroach.

That's according to a new survey that finds one in five teens (19 per cent) with a Facebook profile has either abandoned the site or visits it less than they did a year ago. The exodus looks to be a recent trend, with 68 per cent of teens who have shifted away saying that's happened in the last six months.

Losing interest or finding Facebook "boring" was the reason for 45 per cent, while being more interested in other websites drove 28 per cent away. Friends not using Facebook anymore was a factor for 21 per cent.

Sixteen per cent of Facebook exiles said they drifted away because their parents joined, 14 per cent were driven away by too many adults or older people and seven per cent blamed Facebook for attracting too many younger people.

Only 13 per cent of those who left were privacy-minded and uneasy about people seeing their personal information, and just 12 per cent were unhappy with the changes Facebook has made.

The survey was conducted April 26-29 by Roiworld, an online fashion and gaming site, and included 600 teens age 13 to 17, with a margin of error of four percentage points, 18 times out of 20. It found that teens spend about two hours and 20 minutes a day online and 80 per cent of that time is occupied by social networking sites.

Other social networking sites such as Twitter, YouTube, MySpace, Windows Live Spaces, Pandora and Club Penguin are also popular with teens, with 90 per cent of them having a profile or using at least one social network, while 78 per cent had a Facebook profile.

The survey also found 43 per cent of teens have spent money on a social networking site — 16 per cent of them to purchase a virtual gift and 35 per cent to purchase game currency that allows them to buy virtual items.