It’s basically a simple combination of the PageRank and TrustRank algorithms, both of which have plenty of resources online.
In short, if you’re followed by high-reputation users, your reputation goes up too. The more trusted users vouch for you, the more trustworthy you become.
That sounds reasonable. I suppose at the extremes it needs people of high reputation to venture deep into the noise to rescue those who sit with a Purgatory of ignorance.
A new user only needs to be followed by a regular account to boost their reputation into the top 60%, since spam accounts rarely get any followers, following them would expose the spam account owner.
