LJ - is it possible to catch up with traffic or something more?

Very often stand-alone blogs have mirrors in different blog services. As a rule, they are used for simple crossposting in the hope of catching up traffic.
However, I believe that they can be found more appropriate application. First of all, it is a very convenient platform for communicating with a large audience.
A good example of this is the following discussion in my community.
If you make good money on your blog, then it makes sense to hire a student, let him respond to comments.
Take care of people.