Yes, IPs can't be used to ID a chess account. A single IP could be used by many different accounts, even in one home, and many individuals probably access from multiple IPs-- home, work, mobile device, public library, whatever.
Is chess.com cleaning house?

Banning an IP is simple and certainly within Chess.coms capability. Indeed! I would be shocked if they haven't. It's the first thing a good forum admin does.
As far as cheating goes, I find it terribly sad that someone has invested so much of their self-worth into an online game community that they feel they need to cheat to inflate their image. I speaks of a truly desolate existance. They have my sincere pity.
Unfortunately banning an IP address isn't really feasible... just because there's one cheater in the household shouldn't mean that nobody else from there is allowed to create an account. That would be like putting me in jail because my brother stole a car.
Not to mention many IPs are dynamically allocated and therefore if you ban someone on an IP, that IP might be someone else (another ISP customer) later on. And changing IPs is relatively easy to do so it wouldn't be permanent anyways.
These are the possibilities I was concerned about when I suggested the banning of IPs.

I can't help but to think of the time wasted by these people, some of these people have been on for 3+ years. Generally, I consider your live rating to be close to a person's normal ability or strength. I generally add 300 points to equal roughly your online rating. One guy from my team had a 1620 USCF, but over 2500 online. That makes me think that he has to use significant help to make his moves.
Without question: no true 1620 USCF can hold a 2500 here without considerable aide (sic).
Thats not quite true. You can hold a 1620 rating and not play in matches that would take your rating higher in the federation. But you could have played games and gotten better and hold a much higher rating here.
But, that is a 900 point increase; as I have said subtract roughly 300 points online to be your live/OTB rating. A 1620 USCF has to be using databases to make their moves.

Banning an IP is simple and certainly within Chess.coms capability. Indeed! I would be shocked if they haven't. It's the first thing a good forum admin does.
As far as cheating goes, I find it terribly sad that someone has invested so much of their self-worth into an online game community that they feel they need to cheat to inflate their image. I speaks of a truly desolate existance. They have my sincere pity.
Unfortunately banning an IP address isn't really feasible... just because there's one cheater in the household shouldn't mean that nobody else from there is allowed to create an account. That would be like putting me in jail because my brother stole a car.
Not to mention many IPs are dynamically allocated and therefore if you ban someone on an IP, that IP might be someone else (another ISP customer) later on. And changing IPs is relatively easy to do so it wouldn't be permanent anyways.
@Whitepawn - true. There are ways to get around IP bans (IP benders, proxies, etc) and laptops used in mobile locations are assigned temp IPs. However, assuming a long site history for the abusers, the probability of them having a fixed IP is high, and the work arounds are a pain. While not being fool-proof, it is an effective deterrent - especially considering the ease with which it is implemented.
@Glass8 - the analogy should be more like they impounded the family car because someone was selling drugs out it. The outrage of any fellow IP users who are also members of the site towards the perpetrator can be counted as a bonus penalty, and perhaps an object lesson.

Fortunately, you're not in charge.

I can't help but to think of the time wasted by these people, some of these people have been on for 3+ years. Generally, I consider your live rating to be close to a person's normal ability or strength. I generally add 300 points to equal roughly your online rating. One guy from my team had a 1620 USCF, but over 2500 online. That makes me think that he has to use significant help to make his moves.
Without question: no true 1620 USCF can hold a 2500 here without considerable aide (sic).
Thats not quite true. You can hold a 1620 rating and not play in matches that would take your rating higher in the federation. But you could have played games and gotten better and hold a much higher rating here.
But, that is a 900 point increase; as I have said subtract roughly 300 points online to be your live/OTB rating. A 1620 USCF has to be using databases to make their moves.
That is still an assumtion that I'm not willing to make....

I think I won a game because one of the players "resigned" just entering in a complex middlegame... like he abandoned a lot of games, but the account is still open. I dont get it. Sickness?

Please remember that although ALOT of accounts are being closed for cheating, alot more will be and people want to discuss this, cheat related threads aren't encouraged in these forums.
Having several constant and/or redundant threads on the topic that circulate with the same questions and comments over and over again isn't helpful, and instead causes people to worry more than they need to. If you want to discuss cheating, please do it in this group
http://www.chess.com/groups/home/cheating-forum
Jimebau, they certainly wouldn't ban somebody if there was 'only' a 95% chance that they're a cheater. I'd imagine the cutoff is at least 99.9%.
I would bet that's the case. Maybe one out of a thousand of banned members are actually playing by the rules.
So are you implying that Magnus Carlsen is playing under an alias? I'm sure quite a few masters do this, for whichever reason, seems acceptable. By no means am I defending the cheaters, however some elevated chess players don't use their name?
No, the only implication I am making is that no system is perfect.
I agree with you that the system isn't perfect. I am only trying to defend my own imaginary self, if I was good at chess, and I suddenly got banned from the chess site for being "unusually good." However, I do understand that chess.com has multiple tools they use to decide who is a cheater, although like my previous posts, is not reveiled to us.
Nobody gets flagged for being unusually good, as far as I understand. They get flagged for being unusually computer-like.
That makes sense.
Is there a difference?
I'll answer that question. Yes, subtle differences in positional play, flawless tactics and NEVER any blunders.