i'm an e-pimp and i have a fleet of e-whores working under me. And I have a bottom bitch that manages the other bitches
I'm alwasy work alone,,,, but sometimes i ask my GF to do some simple seo work for me, like follow ppl on twitter, adding friends at myspace and etc. its fun!
I like using a combination of methods as this usually results in higher productivity. Sometimes, it's good to have to worry just about the business aspect of it and leave the backlinking and other laborious material to my employees.
My BF and me work alone. Yes, its 2 people but i say 'alone' cause we are doing very different things, he is web designer/developer and i am doing all advertising/marketing/promotion. Mostly we (or more,he) trust only himself to do his own work.
I will prefer to work alone for small projects and hire people for the big projects. Regarding trusting the people in online, i will only hire well known people to me.