One of the arguments to why there wasn’t support for VoIP in the Lync mobile client was that some (all) of the carriers don’t like VoIP. Now one of the largest carrier in Sweden has announced that they will start to charge a monthly extra fee on all new plans where you simply pay to use free VoIP apps.
When you use Lync on a mobile phone today and use the call via work feature the Lync server calls your cell phone and your mobile will not be charged for a outgoing call. This is actually also something that some carriers have expressed some negative thoughts about, but its technically not possible for them to stop so I guess why bother. But there will probably be some sorts of network limitations on using some apps like Skype and I hope that they wont try to block Lync.