When I was a kid and spent a lot of time planted in front of my computer IM'ing with friends locally and around the world, I loved messaging! There were a few great general IM apps that would allow me to connect to multiple services all under a unified interface. Some friends on MSN? Some friends on AIM? Not a problem, just add those accounts to my preferences. I could see when people were online, the messaging seemed reliable and consistent (for the most part), I was able to see when/if things were delivered, I could see when people were typing a message to me.
15 years later and I feel like people have shifted a lot of their lives to mobile but the solutions we have to work with to communicate are half of what they used to be. Are my friends online? Who knows. Can I see any kind of status if they're an iPhone user? Definitely not. Did the message I just sent actually get delivered? I hope so! Oh, let me launch Skype for two minutes so I can send a message to one of the two friends I have on that platform.