Up to 100000 People on one server or a littel clan server.

Optimal bandwidth usage with codecs ranging from CELP 5.1Kbit to GSM 16.4Kbit to Speex 25.9Kbit for optimal voice clarity
Local addressbook allows you to connect quickly to your favorite servers
Webserver list allows you to find TeamSpeak servers without their IP
Flexible permission system, allowing you to configure your server the way you want it
Channel and subchannel creation
Built-in web administration interface allowing you full control over your server via your web browser
One server-instance can run multiple virtual servers which results in hassle-free administration
Telnet access to your server-instance as well as to all virtual servers
Client is designed to work well with firewalls and routers
Passworded servers and channels
Completely configurable keybindings (hotkeys) to quickly join specified channels, mute your microphone, etc.
Whisper functions so you can speak privately to inidividuals, groups of persons, or other channels
Auto voice normalizing (no need to adjust your mic manually)
Supports Microsoft Gamevoice (TM) hardware
Windows/Linux server
Windows/Linux client
Event driven sound notifications (which can be configured individually)
Text messaging in the client (for those complicated URL's or IP's) and clickable links
IRC-like admin functions for your server (like serveradmin, channel admin, operators)
Channel moderation, which is useful for holding meetings in channels with many users
Kicking / banning people
Seemless optoinal MySQL integration, allowing you to customize your server database
Minimal CPU and RAM requirements
Given bandwidth requirements are met, servers can easily handle thousands of users
· Authorized Teamspeak Host Providers (ATHPs) and other Commercial users can integrate their own clickable banner in the client