AOL Instant Messenger is about to put up an away message forever. AIM will officially shut down on December 15 after 20 years in service, its parent company announced Friday. When AIM launched in 1997, using the World Wide Web required a desktop computer with a clunky dial-up connection that tied up the phone lines. Perhaps more than any other product, AIM helped establish the internet as a place to hang out rather than being a simple utility...A decade after AIM launched, Apple kicked off the smartphone era with the release of the original iPhone. Untethered from their computers, internet users shifted to a range of messaging apps and social networks like Facebook...AIM, with a brand recognized by millions, could have capitalized on this shift and emerged as a lead player in the billion-dollar messaging space. Instead, it faded further and further from relevance.