When you use Internet - like forum or something - not only your mind, but your head/eyes, and neck, and your arms/hands (at least one) are occupied as well.
However, there are activities that don't require much brain: stitching socks, ironing, that stuff. But such stuff demands your hands and eyes, right?
See, not mentioning p2p voice conversation, there's already the chat function been realised: take that Google's "Hangout":idea: (Well, you might need to take a look at the screen occasionally, or push some button time to time.)
See, I think if we can get a further step into the realm of hearing and talking -- well, that would not only be convenient for saving your hands in order to undertake some housework - don't forget that there are people who are limited in their perception.
So, what do you think should be the form of such a service? Should it be fully online? or maybe it'd better require an on-machine application to sustain the voice rendering? (Imagine, when "instead" of a smile the reader will just "haha!" to you, huh? I dream the user could record a post or reply directly - then it will be THE post/reply - with a possible written variant. Otherwise, a typing user could also read up what he/she just submitted - so it'll be 2 variants of the same entry.)
Opera used to include a text to speech engine. The one on Mac OS (same engine as Siri, I imagine?) sounds eerily similar to a real human. So no, it doesn't need to be online.
1. There needs to be be the other way round too!
2. or rather 1a) In this case the script/programme/whatever should properly discern voice input modes -- like you click your mouse here to type some or hit "Enter" or an item in the menu bar...
2b or whatever: and the thing must not only read what you point it to, but importantly, register and manifest other fields on the page, suggest the results for you to pick/proceed, even reload pages and loudly or however else notify you about something and inform you what's "new on the board".