Historic:Synced servers
Altslashdot would be run on a number of independent web servers, which would utilise some syncing protocol in order to serve exact copies. The syncing would likely be cheap, because the number of such servers would be substantially smaller that the number of users.
The possibility of running a server would be open, in a hope, that a relatively large number of these would eventually be created. "Hub" sites might exist, that would redirect to the least--loaded servers.
Beside sharing hosting cost, the architecture would enable the exclusion of a rogue server.
Comments
I'm no programmer, but isn't this how USENET worked?
Yes, it is similar, but we would need much more than Usenet, like safe user base and moderation. And it all would need to be tunneled through corporate firewalls, which often allow only web traffic.