It's even approaching the popularity of e-mail. According to a recent survey by the Pew Internet & American Life Project, 46 percent of Gen-Y'ers use IM more than e-mail. Why not harness the immediacy of IM to spread the word?
At first glance, you might think that IM is like e-mail, with people typing to each other. IM isn't instantaneous email. It's probably more like mobile phone communications than anything else. Contact is personal, one-to-one, and usually among trusted parties. And unlike email, a fairly asynchronous communications medium where users are in total control of what and when they read, IM is intrusive. It pops up unannounced and requires users to make an instant decision about what they're going to do about the intrusion. Simply buying lists of IM handles and sending messages to them is a sure way to draw attention.
People don't have to go offline and slog through a voice-mail menu or send e-mail and cool their heels until it's returned. Studies have shown that e-commerce sites often lose sales because customers can't get their questions answered quickly. People can also IM at the office without others overhearing them.