but I think NotSoChiGuy had alot of good points.. Great example you can set your "status", at lunch, or in a meeting, Do not disturbe, and most of the time you can create your own.
Every IT job I have had we have always used a IM enviroment, and its not that bad. Its a good way to send a quick comment or get information on the fly. I would say ALWAYS "record" all conversations! But those conversations can be edited with a text editor... so it can be altered, I take it as a grain of salt... So if someone says something off color to you, or rude ect... I would screen shot it! So you have two ways to prove what ever was said...
I tend to have a forgetfull memory, and often times I will IM someone asking for an Intranet address, an IP, or a quick how to... So in the future when I forget I can refer back to the chat log...
etiquette issues: It all depends on who you are talking to and what your relationship is.
One thing that can be a HUGE pit fall... just an example: While I was contracted to a massive company 300,000+ users (world wide) all using a messageing service... Well a nice little trojan horse infected one persons PC, then took the IM Service and sent messages to people (in their IM client) with a link. People clicked the link (people thought they could trust the link cause they new who sent it), and got the trojan horse (and so on and so on). That trojan horse carried a virus behind it, and you could find and delete the virus, but the trojan horse would then reinfect the machine... Most AV's coudn't pick up the trojan... Then eventually the virus would run a nice little regedit that would reboot the machine once you logged in... That virus spread SO fast, because people didn't think twice about click links... I would say with in 3-4 days, it infected close to 125 people min. At our location alone, and thats not counting all the other sites.... Thats a headake!!