You assign trust/influence/value-to-you to accounts along contexts - not just "about the person" (which I agree is a problem in the bad version of WoT). 

So you are ultimately scoring their content. If I assign low trust to Laeserin on the "economics" context but high on "religion", then when she writes content on those two topics, it will be filtered (for ME, not anyone else) accordingly.
Now, if you attest about me on these two topics, my view of Laeserin will slightly influence your view of Laeserin (only on these topics), along with your own view of her and others you've attested about. 

The process is entirely voluntary and reputation flows from you. Nobody else can influence your graph if you don't trust them to. There is no global state of influence.