A16Z: Understanding SAAS and why the pundits have it wrong
a16z.com
a16z.com
https://news.ycombinator.com/item?id=7738602
from 8 hours ago.
Also, posted in the earlier thread, there was also a podcast:
https://soundcloud.com/a16z/a16z-podcast-valuing-todays-fast...
Some companies like Workday are harder to replace, but some like Box are vurnable to being replaced by consumer/add-on (Dropbox/Google Drive).