(on Wikipedia)
https://userbase.kde.org/Kopete

An instant messenger.

AIM, ICQ, MSN, Yahoo, Jabber, IRC, Gadu-Gadu, Novell GroupWise Messenger, and more.

Only tested with IRC.

• 2009-04-07 - 0.12.7 (Using KDE 3.5.10) on PCLinuxOS (version not recorded)

• 2007-04-30 - 0.12.4 (Using KDE 3.5.6) on (distribution not recorded)

2009-04-07 - 0.12.7 (Using KDE 3.5.10) ∞

Part of my Steaming pile of Linux instant messengers misadventure.

• Wow, a surprisingly awkward and annoying configuration screen to add a new server. It really does look like it's been made by programmers, with all the variables laid out just so. I was annoyed several times when I tried to add in a server on the right, and pressing enter would add a blank one on the left. Yes, it was the wrong way to do it, but it was laid out like it ought to work that way . Argh. I had to re-do things a few times before I stopped thinking like a regular person and started thinking like a developer. Click button one, go to field A and type input, go to field B and type input. Do not look to the left or to the right. Now click OK. Now go find the thing you just added, because the program won't help you. Now select it, now edit it, now add entry number one... and on and on.
• Umm, no NickServ fields. Sigh.
• Custom CTCP Replies. Umm, yeah. I guess that's an advanced setting if I have to look it up, which I won't. That's probably where the NickServ stuff ought to go.
• "Run Following Commands on Connect". Ok, aside from the bad grammar and inappropriate Title Case, this list is alphabetically sorted. Seriously. I don't mean it's in whatever order you added stuff in, a programmer actually chose to alphabetize the list .
• Spams me with KDE wallet nonsense. I hate KDE so much. Even alt-tabbing back here to write a note on that gave me an extra popup just to piss me off.
• Uh oh, I actually tried to use it. Now I'm in for trouble. Have to add myself as a contact to join IRC. Hrm.
• I still had CenterIM going and so it auto-renamed me.
• Quit CenterIM, re-connected with Kopete and.. it didn't try the original name.

• Quit Kopete, which I had to do with the chat window and Kopete itself. I guess control-q means "oh, just sort of quit a little bit". I restarted it, and. Umm. It doesn't feel like doing anything. I try to "add" the IRC nick I made as a contact, and nothing happens. No error message or anything.

Screw this, it's KDE and I wouldn't really want to keep it in my toolbox anyway.

I wasn't serious about testing this. Testing this program is like the porn star with a fluffer before the main show. Let's try some real software now, shall we.

2007-04-30 - 0.12.4 (Using KDE 3.5.6) ∞

Tabbing should be enabled by default!

(source)
There are several different ways to control grouping. To configure this behavior, go to the Chat tab of the Behavior page of the Configure Kopete dialog. You can also move chats between windows using the Tabs menu, and control the placement of the tabs in the window.

Wow, how non-descriptive. It's actually:

• Settings > Configure > Behavior > Chat >

  • Chat Window Grouping Policy: Group All Messages in Same Chat Window

• It doesn't do the XChat-style horizontal line to tell you what the last thing you read was.