A monetized Posterous could be run on 100 or less servers. Tumblr runs on perhaps 1,500x according to High Scalability, and it's at least a few hundred times more nasty than Posterous in terms of server thrasing (pageviews and hits on the data via the dash).
Posterous would never be a billion dollar service, but it could be the type of service that generates $10m+ in annual profit.
100 servers from a competent host + bandwidth via a pooling deal = less than $50,000 per month. It wouldn't be sexy, but it'd hold.
I wouldn't keep the current Posterous business model of chasing Tumblr into a pool of red ink. I'd place a bet that users will pay for a service that will stick around. It would reduce usage, but there's a large base to monetize that would be willing to stick around.
1m pageviews a month is about equivalent to 10/second. A single app server can handle that easily. Add on a redundant app server, two database servers, and some static/queue/mail ones, and you're looking at 10 servers _tops_ for that level of traffic (and much more).
It's obviously 30 million monthly pageviews (I said 1 million daily pageviews, I think you misread my text).
100 servers would assume media hosting for images and other files that go with a blog. That could all be kicked out to other services like Amazon, but the costs would obviously go up and I don't think it would be necessary.
At $500k +/- a year in infrastructure costs, I think Posterous could be wildly profitable. You could run a tight ship with five to ten people (throw in $500k to $1m in employee costs). If someone put a gun to your head, it could be maintained with a two or three person team.
I mistyped my original response. 1 million daily pageviews is still 10/second. The rest of my post remains the same, so 30 million monthly pageviews can easily be handled with 10 or so servers.
Tumblr daily pageviews: 500m; Posterous daily pageviews: 1m
Posterous would never be a billion dollar service, but it could be the type of service that generates $10m+ in annual profit.
100 servers from a competent host + bandwidth via a pooling deal = less than $50,000 per month. It wouldn't be sexy, but it'd hold.
I wouldn't keep the current Posterous business model of chasing Tumblr into a pool of red ink. I'd place a bet that users will pay for a service that will stick around. It would reduce usage, but there's a large base to monetize that would be willing to stick around.