1 - Bold and Italic - Facebook used to allow you to make use of bold and italic text, however, following the merger of messages and chat messaging that functionality has been removed.
2 - Emoticons - Every so often Facebook introduces new emoticons without warning or announcement, for example in addition to the commonly known shortcuts for emoticons (y) and (n) have been introduced two months ago.
3 - Desktop Messaging Clients - You don’t need to use Facebook on your browser to access Facebook chat. You can make use of a Facebook windows clients such as Chit Chat for Facebook. Chit Chat makes it possible to connect to Facebook chat from your desktop. Main benefits include tabbed browser window, ability to use a proxy and being able to discretely use Facebook chat without having Facebook open. This Facebook chat add on is free to use.
4- Not Real Time Status - Unlike other instant messengers such as AOL and MSN, Facebook chat isn’t a real time instant messaging service. By this, I mean that the service doesn’t update your status to all of your friends immediately as soon as you come online. Your status, and indeed, your friends status is refreshed - and therefore updated, every two minutes. As such, this means that there is a period when you sign in when you won’t appear to be online - and a period when you sign out when they’ll still appear to be signed in.
5 - Mobile Messaging - It’s possible to make use of Facebook messaging on your smart phone, albeit a Blackberry, iPhone or Android enabled mobile phone. The official Facebook app won’t sign you in by default as it’ll consume a lot of your battery life. Unofficial applications such as “Chit Chat for Blackberry” that allow you to access Facebook chat on your Blackberry tend to offer a richer experience, however, you’ll need to know your Facebook username.
6 - Facebook Usernames - Facebook chat is based on the open source technology XMPP much like Google Talk, and as such, Facebook chat is actually connected based on your Facebook username rather than your Facebook email address. Some Facebook tools will look up your Facebook username for you when you type in your Facebook email address to connect you to Facebook chat. Your Facebook username is the custom profile address page that you selected so if your profile page is http://www.facebook.com/yourprofilepage then your Facebook username is “yourprofilepage.” Your password for your Facebook username is the same as for your Facebook email address.
7- Facebook Messages & Facebook Chat are now the same thing. Facebook have integrated both Facebook messages to the same messaging system, moreover, Facebook allows group chat. However, group chat is only supported on Facebook.com and not on third party Facebook tools as the API for this has not yet been released yet.
8 - Market Share - Facebook chat is reducing the amount of messages that users send on other third party instant messaging services. That said, business users still tend to prefer other communication networks such as Skype, Google Talk and Windows Live Messenger due to its better reliability.
9 - Blocking - You can’t block individuals on Facebook chat, but you can block groups of people . Alternatively, you can limit yourself to chatting with certain user groups. In order to access the “Blocking” functionality you need to click on the gear, click “limit availability” and select the groups you wish to include in blocking/your availability.
10 - Chat Spam? You can report chat spam to Facebook by clicking on the instant messenger session and selecting the gear, then clicking “Report Spam.”
