Seems like a pretty crappy theory actually. Why are thoes things not built in an unchangeable charter (or something like it).
Also FB is making $1 per year per user atm (storing photos,messages and heaps of other stuff). Why does dalton need $50 per year to store 140 character message?
Edit: Turns out there is a charter called "core values"
My guess is that he's asking for $50 because he doesn't want to attract people who won't extract significantly more than $50 worth of value.
Regarding your comparison to FB: price is certainly not just about cost; it can also be about establishing the right signals to potential customers and non-customers. In this case, I suspect the signal is "if $50 doesn't seem like a great deal for this product, you're not the target customer".
Aside from attracting a particular kind of customer just by setting a price at all (e.g., eliminating huge swaths of automated spammers), this can potentially create a positive network effect. If you're someone who wants to follow a social news feed, which society sounds better: the one where everyone involved cared enough to put up $50, or the society where botnets can easily create thousands of accounts per day?
There's a lot to be said about free-for-all ecosystems; but they're not the only solution.
