IBM Lotus Sametime 8.5 represents the next generation of unified communications and collaboration software:

• A new online meeting experience that is integrated into the IBM Lotus Sametime Connect client. Join a meeting with a single click. Easily invite others by dragging their names from the contact list. Accept meeting invitations with a single click. Upload meeting materials via simple drag and drop.
• New zero-download, browser-based chat and meeting clients that extend the desktop experience to wherever the user is working.
• A new standards-based audio and video infrastructure that enables more seamless interoperability with third party audio and video conferencing systems.
• New audio and video codecs that provide higher quality native voice and video services for a more compelling collaborative experience out-of-the-box.
• New Web 2.0 APIs that let developers embed Sametime capabilities into Web sites and applications so users switch context less.
• A new, browser-based Apple iPhone chat client, support for the Blackberry Storm, and an improved mobile client for Microsoft® Windows® Mobile devices.
• New social views that make it easier to find the people you collaborate with the most.
• Deeper integration with Microsoft and Lotus products

Source: Sametime Blog