There was yet again another new announcement this week on Lync App for Windows Phone, iPhone and iPad which can be used with Lync Online.
The big news is the Lync App now supports the ability for attendees to join a meeting without a Lync account (as a guest) using the app. With this capability allows people to use the Lync Audio feature (without having to dial-in) to participate in the meeting. They can see all the content, including desktop sharing on their mobile device. This is huge feature because it allows organizations to easily allow people from outside of their organization to attend meetings without having to dial-in or be on a computer with the full Lync client.
Additionally the Lync App was extended to allow for ad-hoc, multi-party meetings to be initiated by the mobile device.