I don't think so.
http://twitter.com/tos
> We encourage and permit broad re-use of Content. The Twitter API exists to enable this.
twitter lives from reproducing other people's stuff.
> Except as permitted through the Services (or these Terms), you have to use the Twitter API if
> you want to reproduce, modify, create derivative works, distribute, sell, transfer, publicly display,
> publicly perform, transmit, or otherwise use the Content or Services.
just use their API.
Which presumably most people do anyway ... unless you are a programmer.
I assume this is because they don't want people to copy large amounts
of their stuff and process it so to make a twitter2 from it
many news are now most actual at twitter.
I remember earthquake,wikileaks,pandemic
and of course conspiracy theories...