I have a Samsung Galaxy Y and I once clicked a sponsored link that appeared when I was playing Angry Birds. It was an app to help battery power - my battery power drains very fast despite being only 2 weeks old.

Anyway it came up warning me not to install apps that weren't from Android market and Avast antivirus also flagged it as a threat / trojan. So I have steered clear.

Do you have any apps that aren't from Android market? Is it a big no no to install them?

I've used a couple, but only when I trust the supplier - currently the only one I have is the dropbox beta software

just because something is in the market, doesn't mean it's safe mind see:

http://forums.digitalspy.co.uk/showthread.php?t=1600330

its pretty risky. If they choose not to host it on Android market there's usually a good reason for it.

Having said that, from reliable sources, it can be handy to circumvent artificial restrictions on country and phone model availability. See the Sky Go for Android thread for an example.

I *would not* get an app just from an advert. At the very least a google to find a reputable site that's recommending it.

(If you're not sure what would qualify as reliable sources and reputable sites, you probably should stick to Market)

There's also the Amazon App store, but that, in theory, is only for US customers at the moment.

is viber okay??

Your battery drains quickly if you play games on your phone. There are lot's of battery 'Aids' on the official market. You shouldn't need to get any from an unknown source.

available on the market
https://market.android.com/details?i...ber.voip&hl=en

Apps from adverts? Never. Apps from torrents? Never (don't cheat the devs). Apps from forum sources? Yes, this can be OK. On my android tablet I know that Opera 11.1 and Flash 10.3 work better than the updated versions on the market. These are the type of reasons I would go "off market". Battery saving apps are crap anyway but there are plenty to chose from on the market.

Have a copy of Google Currents which isn't available in the UK yet, got it from a reliable source though so... wouldn't risk it from a random link/torrent.