Earlier quoted context omitted.
Nothing happens immediately --- the regional authorities still have some free space left, although some are planning to get more stingy. (The discussion here --- http://en.wikipedia.org/wiki/IPv4_address_exhaustion --- is at least a starting point for the curious. FWIW, the first that's likely to really run out is APNIC, for the Asia/Pacific region, within the next three to six months; the RIRs for Europe and North A…
What I don't understand is what happens to website hosting? Will the cost of a Linode go up? Will they be able to get IP addresses for new customers?
As a basis for making up your own mind: Linode has, at the moment, nine /20's allocated. At 80% utilisation, that means roughly 30'000 IPv4 addresses.