I feel like I am slumming by blogging this, when for me this would be better off as twitter blather.
Twitter is giving me deja-vu memories of Friendster.
How did Friendster solve their problems?
They latched on their graph engine to the internals of MySQL, and pushed joins into the database.
Anybody up for writing a quick queue engine? I bet you can figure out which website really needs one about now...