Queen B here, giving to LD on IM. I had first experienced IM while a WebCT student @ UNT studying for my MLS. It was with AOL and it was FREE (remember those annoying discs in the mail), so I used it. I was a bit distracting while I was studying. Fortu8ly, now you can turn it on and off. Unfortu8ly, if others see UR online, they may distract U. Of course the texting vocabulary wasn't down to an "official" language as it is now.
Now in a library setting, it could be useful for those seeking answers to questions and book requests. In a library setting that has more than one employee, it could work. I'm the only one in my school library, so it can be a challenge. On busy collaborative days, I can go most of the day not seeing my computer, so if I'm not checking my e-mails, I definitely not responding to IMs. I also get distracted easily sometimes and bounce around based on what captures my fancy (notice I'm doing these Things out of order).
Still, I'm intrigued. I do want a phone will a full text keyboard. I'm learning the texting language. I even read ttyl from the Internet Girls series by Lauren Myracle (ttfn and l8r,g8r are the other books in the series) to try out my skills since the series in entirely written in IM/texting language. Until then keep reading.