Plug-ins for conversations and contacts

I've tried android devices and iphones but I've never seen a solution for electronic communication as great as the plugins for conversations and contacts.

I just power on the N900 and it automatically connects to skype, gtalk, sip, jabber..... and it stays connected and online.

With android or apple devices you have to open a separate app for all these things. The app might be suspended in the background, or the app might crash, or the device might reboot, or power management might shut down the data connection.... any of those things might disconnect me from the various online communication services I use.

Also, if I wanted to talk to someone, I had to check all the various apps to see which service they were online with. On the N900 I got all that information in one place in Contacts.

Has anyone ever seen something like this on another platform?

no
this is why Maemo.org has taken a life of its own after NOKIA abandoned it...

Blackberry has gotten almost there. They are still seperate apps but they integrate well with the hub, good thing is that you don't need to make sure you keep them open, bad thing is that you have to open them to communicate.

Windows phone is very good at this and it also combines conversations with the same person in a single window despite various methods of communication so you can continue conversation over various mediums. Downside is that it doesn't have so many plugins.

The N9 is almost as good as the N900, everything works the same with the bonus that it has a skype icon for those that never delve into the account settings. If it also had skype videocall it would best the N900, but for now the N900 is still the communications' king.

Hope sailfish will handle IM like maemo!

I broke the USB on my N900 for 6 months ago, and have been using G. Note 2 since. And I'm missing maemo's brilliant multitasking, IM, native X and the physical keyboard of the N900 each day.

WebOS was the first to do this. They combine chat conversations with sms. But did not have that many protocols supported.
I just moved to N9 this week. Did not put my sim in it though. But it looks like it has the same system vor conversation as N900, all connection options in the contact card.