>>(1) how the chat room will be when lots of users in it? for example 50 users
50 users are not many users.
>>(2) how about the security of the chat room? if someone in a bad faith and try to do something bad to the chat room
You have the following solutions.
1. Set the password-protected room
2. Kick the abused user
3. Set bad words filter
4. Ban the IP of the abused users
asp.net Chat http://cutesoft.net/ASP.NET+Chat/default.aspx
Web Messenger: http://cutesoft.net/Web-Messenger/default.aspx
asp.net wysiwyg editor: http://cutesoft.net/ASP.NET+WYSIWYG+Editor/default.aspx
asp wysiwyg html editor: http://cutesoft.net/ASP
asp.net Image Gallery: http://cutesoft.net/ASP.NET+Image+Gallery/default.aspx
Live Support: http://cutesoft.net/live-support/default.aspx