It’s not really meaningless babble anyway! And this is not necessarily a bad thing.
Most conversation is not important for the words we speak. Instead it is the act of being present to the other person and giving attention that gives most conversations their true value. Some experts term this social grooming.
It also enables the growth of social bonds by means of the time spent in relatively trivial communications. These seemingly unimportant communications are what makes dealing with bigger issues between individuals and groups easier.
How much easier is it to ask for help from someone you’ve known socially for a while than a stranger? How much easier is it to know the best way to phrase a suggestion or request to someone if you’ve chatted with them before?
The important thing that social networking tools like Twitter or Facebook (or newer tools like Google’s Buzz) enable is non-localised proximity. No longer do you need to run into a person in the office kitchen each day to build up informal social ties. Now we can do it from half a world away in real-time.
It’s also worth checking out Dunbar on this kind of thing.