Lync Online meetings enable users to connect from virtually anywhere through PC-based audio, video, and web conferencing-both as scheduled meetings and as ad-hoc collaboration sessions. With Lync Online, users can collaborate, share information, and coordinate their efforts in real time, all within context. Lync Online supports an integrated conferencing experience, enabling users to join the same conference from the PC (via the Lync 2010 client) or from a phone (requires a separate PSTN audio conferencing service).
Microsoft Lync Web App is a browser-based version of Microsoft Lync 2010 that allows people who are using a computer that doesn’t have Lync 2010 or Microsoft Lync 2010 Attendee installed or who do not have a Microsoft Lync Server 2010 account to participate in online meetings. It’s a program that takes up very little space on your hard disk drive and is relatively quick to set up and start using. It is designed mainly for external partners who are invited to Lync meetings, but it is also useful for employees who are not at their usual computer at meeting time or have not yet upgraded to Lync. With Lync Web App you can view information of all the other participants, send an instant message, share a file with the participants, save a file that another participant has shared, share your screens with others, give a power point presentation, open a whiteboard and conduct a poll between the participants. Lync Web App does not support other Lync features that are outside the meeting experience, such as presence, contacts, IM, and telephony features.
Microsoft Lync 2010 Attendee is a conferencing client that allows users without Microsoft Lync 2010 installed, to participate in online meetings. A user with an administrator account on the computer can install Lync 2010 Attendee so that users of the computer can join Microsoft Lync Server 2010-hosted meetings. Microsoft Lync 2010 does not have a separate Live Meeting client. Meeting functionality has been built into the main Lync 2010 client. In order to allow Windows users who do not have the Lync 2010 (licensed) client software installed to join in Lync 2010 meetings, these users will need the Lync 2010 Attendee Client. This client does not require a software license to use. This is an alternate to Lync Web App which is almost built for the same purpose. Lync Attendee is publically available for download online.
Talking about the Lync client itself, that is of course the most appropriate way of connecting to a Lync meeting since all other methods are just substitutes for this method which actually uses the complete Lync client suit in which this functionality is embedded by Microsoft.
Lastly there is another way of connecting to Lync meeting and that is through dial in conferencing. This is an optional component that one can set up when you deploy Microsoft Lync Server 2010 communication software. Once it is set up, the user could connect to a Lync meeting using the Lync for Iphone application or the Windows phone application which is convenient since users can connect to Lync meeting using their cellular devices!