Instant messaging (often shortened to simply IM) is the exchange of text messages through a software application in real-time. Generally included in the IM software is the ability to easily see whether a chosen friend, co-worker or "buddy" is online and connected through the selected service. Instant messaging differs from ordinary email in the immediacy of the message exchange, and also makes a continued exchange simpler than sending email back and forth. Most exchanges are text-only, though popular services, such as AOL, MSN Messenger, Yahoo! Messenger and Apple's iChat now allow voice messaging, file sharing and even video chat when both users have cameras.