FutureLearn Use Case: factors to consider

Content delivery networks take the complexity of arranging fast and
efficient international network delivery of media files.

The web hosting cost as defined by a content delivery network is
defined by the amount of data being transferred.  The factors that
need to be considered are the amount of data used per MOOC, and the
number of MOOCs that are currently available, and the number of
active users who are downloading each MOOC.

We know that (1) FutureLearn claims to have 7.1m users and 700 MOOCs
and that (2) the six-week Web Science MOOC that UoS created with
FutureLearn in 2012 has 32 x 15minute videos and that (3) 1 hour
of high quality video requires about 2Gb of storage. In addition
we know that cloudflare charges about 1 cent/penny per Gb of
data transferred per end user per month.

The discussion tried to finesse the typical size of a MOOC (more
often 2 weeks rather than 6 weeks), the number of active subscribers,
the number of active MOOCs and the number of courses that an
individual user might join to come up with a more realistic estimate
than "every user has seen every resource on every course" ie 7.1m
users * 700 MOOCs * 8hrs video * 2Gb * $0.01 = $800m.


Other factoirs that were raised but weren't pursued were:
- attrition rate for course subscribers
- video quality vs data size
- device vs video size

Supplement: 11th Janjuary 2019
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Here is the acual analytics for FutureLearn for the month of November 2018:
* 23,569 active videos (i.e. how many different videos were played)
* 81,932 video plays
* 209,075 impressions (“The number of times your videos have been loaded (but not necessarily played)”)
* 78.2 TB bandwidth usage