Since you're new, I'll go ahead and let you know this is the first place you should have come to. As, this is the Private Server History page. Let's get started :)? iCPv1
iCP v1 was just a basic private server, there were no commands, and it was only a for a few selected people. I myself, did not participate in iCPv1, so I can't really tell you much about it other than that If you have any more information about v1, please tell me in the comments. I'd be glad to add it!
iCP v2 was the first very popular Club Penguin private server created by iRath. It was a great start to the Club Penguin private server community. This was also the first private server with commands introduced. The registration and such was available at http://cpps.gotdns.com It gathered many users quickly. However, it did suffer from many flaws.
iCP v2 suffered from many things. Imbalanced commands, for example. You were able to make your penguin larger, so people were covering the screen, making it impossible to move, (a huge annoyance) and it crashed the server too. Another flaw was a poor staff, iCP v2 did have staff members, but nothing was really organized.
iCP v2 shut down in June 2010, because iRath apparently was overwhelmed and felt unappreciated. iRath was in the middle of making iCP v3, the next version of iCP at the time. Many people thought that was the end of iCP, (Club Penguin private servers) but then several people said people began making iCP v3…
iCP v3 first began in late June, by different people than in iCP v2. It first started up as a forum, while they developed it. It was then released in early July, it was an explosion. Many people joined, and it soon had thousands of users. It had a much better balance of commands than iCP v2, and a very well organized staff.
iCPv3 was the private server that caused the original surge in Club Penguin private server popularity. It gained over 100,000 users, and then a supposed Cease & Desist from Disney resulted in the server being shut down.
I feel as if I should not update this for when every private server comes along, but I will update it when something as revolutionary as iCPv3 comes along, and stays online for more than a month. (which has yet to happen)
- Credits to Roman and Private Server HQ