What's the deal with some people showing up online and offline over and over again on facebook chat?

[Purple Haze]

I'll see some people, one girl in particular, who will have the green dot then just the mobile sign then the green dot then the mobile sign over and over for HOURS and the green dot wont last for long...sometimes for just a second.

What's the deal with that? Is that what happens when you open up the facebook app? You get shown as online? And she's just checking her feed like crazy? lol. There's no way this girl is just sitting at her computer going on and off chat for hours. Its so weird and I see it happen with her a lot

[Chelss]

It shows the green light when they are active and the Mobile icon when they are "idle" but available on their mobile device

[jrddecker]

It depends on the app she is using, but I know my old one used to put me on green every time I opened my phone to check a text, check fb, check the time. Anything. and then go red again when the phone went back to idle

[Jeanne]

she is using Facebook app, that is she is in online always

[Googleplex]

It's because Facebook is actually not that good and their programmers are not much better. If they were good, they would have made something which either keeps people on or off.