There are plenty of folks who do that. And some clients do support that behavior. But the problem with an etiquette based solution is that there is a fair amoun

There are plenty of folks who do that. And some clients do support that behavior. But the problem with an etiquette based solution is that there is a fair amount of bandwidth consumed by discussions of what is and is not appropriate etiquette. Client-side filtering does break the implied 'I read your every brainfart' contract that makes twitter appealing to so many, but come on; this just moves the filters a little ways outside your head.