It doesn't replace phone, email, face-to-face or NNTP, it's just another tool that's good for what it's good for.
We're mainly using MSN and Exchange IM: main benefits are presence info - although it's not 100% accurate, it's really useful to know if somebody's likely to be at their desk.
Biggest plus for IM itself seems to be the ability to establish a new channel of communication while on the phone e.g. during a boring conference call (lots of those!) or while on the phone to a customer, without having to put them on hold. Also e.g. for PAs using IM to pass short messages to their boss while the boss is on the phone.
Less importantly are the ability to share small bits of text very quickly (e.g. it's quicker to pass a long URL to a colleague at the next desk via IM than via email), and the ability to launch voice chat and desktop sharing quickly and simply - the MSN IM implementation is far more immediate and accessible for users than NetMeeting.
Downside, if you think of it as being a downside, particulary using a public service such as MSN is the amount of private trivia conversations ("have you had your lunch yet, honey?").
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We're mainly using MSN and Exchange IM: main benefits are presence info - although it's not 100% accurate, it's really useful to know if somebody's likely to be at their desk.
Biggest plus for IM itself seems to be the ability to establish a new channel of communication while on the phone e.g. during a boring conference call (lots of those!) or while on the phone to a customer, without having to put them on hold. Also e.g. for PAs using IM to pass short messages to their boss while the boss is on the phone.
Less importantly are the ability to share small bits of text very quickly (e.g. it's quicker to pass a long URL to a colleague at the next desk via IM than via email), and the ability to launch voice chat and desktop sharing quickly and simply - the MSN IM implementation is far more immediate and accessible for users than NetMeeting.
Downside, if you think of it as being a downside, particulary using a public service such as MSN is the amount of private trivia conversations ("have you had your lunch yet, honey?").