Mercury is a Java-based MSN client (and upcoming Jabber client).

Here are some key features of "Mercury":

· Talk to friends
· Change your nickname and status
· Add a display picture (also know as avatar)
· Send files through the msn server (for people with a firewall etc..) or direct
· Play games (Tic Tac Toe and Connect4 only at the moment)
· Watch the webcam of your friends (Mercury auto-saves these sessions on the disk and can convert them to Quicktime movies, click here for more info)
· Allow other people to watch your webcam
· Video conference is implemented (both sending and receiving) but still a beta feature.
· Send and receive winks (sending custom winks doesn't work yet due to new security restrictions in MSN7)
· Personal messages
· Current song for winamp on Windows and ITunes on Mac OS X (latest beta has an option to set execute a shell script to get the current song)
· Nudges
· Support for multiple operating systems, you can run the same Mercury version on Mac OS X, FreeBSD, Linux and Windows. So the Mac OS X version isn't 2 years behind ;-)
· Be online with several MSN addresses at the same time.
· Login with your status on 'Invisible' or any other status you want.
· Have a different MSN name in every conversation (Personal name)
· Use and create your own plugins
· See when someone starts a conversation with you before he says something (this has been removed from MSN7, Mercury will now show when someone starts typing, this is the closest I could get to the old function)
· See when someone closes the chat conversation window.
· See who added you into a conversation with multiple people
· See when someone deletes you from their contactlist.
· See what MSN client version someone is using (or emulating, Mercury currently emulates 7.0)
· See if someone in your list is using Mercury
· See if someone in your list has a webcam (if he/she allows you to see it)
· See your fake, faked and ghost friends
· All avatars downloaded are stored on your computer in PNG format (96x96)
· All webcam streams are stored on your computer, you can convert them to a Quicktime movie if you want or watch them internally using the webcam stream player
· All personal emoticons downloaded are stored on your computer
· Avatar scroller, automaticly change your avatar every 5 minutes
· Background image scroller, automaticly change backgrounds every x minutes
· Send larger avatars then normal
· Override someones avatar
· Enter notes while in a conversation you might need later (date of birth, last name, phone numbers)
· Away message, if you are online, busy or whatever you can always have an away message.
· Disable the away message in a conversation so you don't see that annoying message when you just want to talk while appearing away to others
· Auto log chat conversations, always log your chats so you can read back everything that is said between you and your contacts.
· Auto login multiple accounts on startup.
· Auto away, change your status to away (or anything else) after x seconds of idle time (Windows only)
· Auto update when a new version is available (Mercury asks if you wish to update when new version is available)
· XML and text based chat logs
· Customise all menu bars.
· Customise your contact list:
· Hide offline contacts
· Show contacts by email, MSN name, alias or a combination of the above, supports multiple lines (List view)
· Change the status icons
· See the difference between contacts using Mercury, contacts having a webcam, fake friends and more
· Show display pictures in the list (lastest beta release allows you to specify the size of the image in the CL)
· Show emoticons in the list
· Sort contacts by group, status or both
· Show contacts in the program by email, MSN name, alias or a combination of the above (General view)
· Add new status icons
· Mercury has 10 custom skins and 3 java skins
· Send screen shots to your contacts
· Add more then 12 users in one conversation (MSN messenger limit)
· Specific triggers for each person (trigger = action after chat event)
· Supported actions for a trigger include sound, a popup window, a windows balloon (balloon=Windows only), shaking a window
· Support for Growl
· Special codes in your name.
· Nick scroller, change your name every 30 seconds into something complety different (allows the usage of the special codes)
· You can use 'forbidden' words in your name.
· You don't have to worry about Messenger worms and virusses, they wont work on Mercury(Windows only :P)
· Text recall.
· XML based setting files.
· Downsides of Mercury:
· It requires a pretty fast computer if you want to take full advantage of all it's functions. Since I am using Swing to display the user interface almost no native widgets are used. This can slow things down on older computers.
· Not sure if you can call this a downside, but Mercury was not made to be exactly like MSN Messenger. It might take you a few seconds longer to find an option you need. I'm not trying to make a MSN Messenger clone so the user interface is different...