While I was writing about the IM/VoIP framework Telepathy last time I found several other things related to this topic which are quite interesting, but all happening below the threshold of the public. Here is a summary of what I found, every comment with more information is highly appreciated!
Decibel (and other ideas)
The situation of IM/VoIP on the Linux desktop is at the moment depressing: there are several clients which most times have their own protocol implementations, different features and different develop state. Also the integration with the underlying desktop is different and no solution is close to perfect – as an example, you cannot just move a file over to a contacts list to send it: you have to choose the protocol, you have to think in advance about topics like “can I send with this protocol” or “the protocol can normally do it, but is this part implemented in this specific client?”.
There are projects adressing this, and one of these was completly new to me: KDE’s Decibel.
The aim of this project is to provide real time communication services (Text-Chat, Audio and Video Conferences) which fits exactly into your workflow. It should not bound to any application. The idea is to think in components and services, each optimized for a special task (or role). As a component will realize the user interaction, the services will provide the technology. Finally, a service-based architecture interconnects all of them to fulfill a given task.
According to the homepage Decibel will integrate all possible IM/VoIP/VideooIP solutions into one point and automate as much as possible – the user should not think about things like protocols and different clients, just about the tasks he want to accomplish. Decibel will do the rest: checking for available protocols and implemented features, checking on which the other side is reachable, checking if this fits together and the task can be performed, perform the task.
Decibel itself is a KDE4 project (think of it like Plasma, Phonon, Solid, Oxygen, …) and has some prominent supporters: the Team page for example lists Eva Brucherseifer, the current head of KDE e.V. As supporters you will find the non-profit organisation NLnet as well as the company Basyskom.
Decibel itself emerged from the the OpenCDI and the KCall project, and was originally thought as an KDE integration of the Telepathy framework. But it looks like that they are using Tapioca know, at least according to their newest homepage decibel.kde.org.
The project is just taking off right now – the homepage is not officially introduced yet, the e-mail list is open for discussion first since yesterday (but the first mail is already interesting), and there is quite a lot of work to do.
Things which are not clear to me at the moment are: what is about the Kopete integration? How will Kopete be integrated, is there any talking or cooperation ongoing with the Kopete guys? Why have you chosen Tapioca and not Telepathy (more about that); even I do not really care because I have to less technical knowledge I guess that other people will start ask this question soon, especially because other projects aim at using Telepathy. All I know yet is that there have been some misunderstanding on both sides, and everyone points at the other side. To get a better picture, have a look at the mail-thread by yourself
And to not only talk about Decibel: there are other attempts to address the mentioned Problems: Ubuntu’s MOTU project also tries to show possible solutions. MOTU has some of Telepathy’s developers in the main team.
Frameworks in the background
As I already mentioned, the one basic component of the solutions mentioned above is a backend-framework that provides all the IM/VoIP/VideooIP functions the user need. One of these frameworks is Tapioca, the other one I know until now is Telepathy.
Both are foloowing the same idea basically, and both are including similar software components (namely libjingle, FarSight and Sofia-SIP).
Telepathy, on the one side, is listed as an official freedesktop.org project and the already mentioned MOTU project of Ubuntu shares some developers. Tapioca on the other side seems to be the favourite solution for Decibel now (in older publications there is Telepathy mentioned everywhere, seems to me that there happend a break somewhere, would be interesting to know why) and is supported by Nokia.
But, again, Telepathy is the client for the Nokia Tablet 770.
At least, that it is how it looks like to me at the moment.
The relation between these two projects is somehow unclear to me – but at least there is discussion going on between these two projects on IRC, so from a code sharing to a merge everything is possible (but also every negative reaction if something bad happens, they are also just people).
This is all I found, if there are any other, additional information, please point them out in the comments, I will probably update the article and include them in important cases.
/home/liquidat 
We (Telepathy) have agreed with Tapioca to merge the two projects together. This means we will be using the same specification (Telepathy) and start sharing the code that they have with ours. Since we both aim to deliver the same thing there is no point in splitting our manpower and create yet another KDE/Gnome rift.
Thanks for the hint, although I have to admit that I already knew that, and wrote about it here :).