my sister wants to start her own website with an Adsense account but the problem is that i think i m gonna get in trouble with my account, because it is two adsense accounts using same IP. is this a problem or not?
It could be. Best to drop Google an email to clarify the situation and to find out exactly where you stand.
If I understand you correctly - you and your sister host separate sites at the same ip and want to use separate adsense accounts - that's fine. If it weren't, Adsense wouldn't work for the many thousands of shared hosting sites. Almost every website you visit, with the exception of the very largest, probably shares its hardware and ip with several others - that's "shared hosting" and without it, most of the folks here couldn't afford to run a website - dedicated sites cost much more money (though not as much as they used to!). It's also fine to run someone else's Adsense on your site - for example, if your sister wrote an article for you and you wanted to give her any Adsense earnings from it - you'd just use her code on that page. This DP site does something just like that to share Adsense revenue and a number of other sites share revenue the same way.
Things have changed, although I don't know the extent to which they have. It used to be the case that only one account per household was allowed, however, that was back in the early days of Adsense when it was just kicking off.
thanks guys for ur help! though what happens with CTR? the fact is that my sister is kind of young and stupid, so i dont want google to ban me because they say i click an ad when she was the stupid one. so the problem everyone talks about being banned is not based on the IP???? i just dont get it, i mean i just dont want google coming to me saying i click an ad because i am completely careful about that. we usually use different computers, but if we login on the same computer, i must tell her to avoid visiting my websites, right? i always remind her to avoid clicking any ad on my sites.
I think this is ok .I even ask google if one web site can put two account ads .Their answer is ok ,too.Just make sure not to click the ads .
thanks! it is good to hear i wont get in trouble if she starts her own adsense account sharing the same internet connection.