So, I've gone to great lengths to craft mail filters to sort my incoming deluge of company email. I know the offenders who send me volumes of useless junk. I've got filters for all of the distribution mail that comes out of every level of the company. I know that once caught by the filters and diverted to one of many folders, I can spend little to no time actually reading the contents of the folder because there's little to nothing that's actually useful in those emails so going through the list once a day (or less) is a short task. The few internal emails that end up actually landing in my inbox tend to be useful and contain information that I actually need to process. But since there are so few of them I can devote time to processing them.
This is a great system. I end up getting very few interruptions during my day. I can concentrate on my work and get into the zone while I'm digging through my software and I can get something done.
But this guy wants to take away email and replace it with instant messaging and other intrusive communications services that demand my attention whenever some boffin decides to tell the world that he's updated some tool that I never use? Great. Now I have to deal with that crap that I've carefully figured out how to ignore. Instead of having a system that lets me address communication when I have time to do so, I have to now use a system that interrupts me whenever anything is being sent to me, whether the message is important or not. Instead of being able to focus on getting work done, I have to deal with a constant stream of interruptions. Good luck trying to focus on anything when your messenger is constantly pecking at you for attention on an irregular basis.
I suppose it's possible to configure messengers to filter and limit interruptions. But then if you filter the incoming messages so you can go back and read them when you have the time, you may as well just use email since that's better at that style of communication.
The switch to alternate forms of communication doesn't solve the underlying problem that far too many people spam out far too much useless information. My solution to the information overload problem in email is to first get rid of distribution lists and limit the number of recipients for a single email to a very small number. Say 20 people or less. If you need to send information to more people than that, come up with an internal web site where you can post distribution information that people can go read when they feel like reading it. Despite assertions to the contrary, there is almost no need to spam large groups with distribution email.
If you do that, you'll find that information overload will be significantly reduced overnight. Those organizational announcements and IT bulletins that nobody reads won't be filling up everyone's inboxes. The release announcements from the tools group that no one really cares about won't clutter up your inbox. The self important idiot who wants to tell the world about his 3rd quarter financials won't be able to bother people who don't care. The idiot who feels the need to post that he published something on the website won't be able to bother you. End distribution lists and you kill a large contributor to information overload.