Many programming courses use bank accounts as examples of race conditions in concurrent systems, eg.
User withdraws £10 from ATM User receives £1000 salary Balance
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ATM looks up balance (£100) Bank looks up balance (£100) £100
ATM subtracts £10 from value (£90) Bank adds £1000 to value (£1100) £100
ATM dispenses £10 note Bank sets balance to value (£1100) £1100
ATM sets balance to value (£90) £90
An account is exactly that: an account (log) of what has happened:
Debits Credits
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ATM withdraws £10 Salary adds £1000
Blockchains are a way to keep such accounts, in a consistent way without giving any one entity control over updates.
For example, the article's Web site ownership system might keep an account with entries like this:
User A transfers example.com to User B
User B sets example.com IP to 123.123.123.123
User A transfers example.com to User B
User B sets example.com IP to 123.123.123.123
User B transfers example.com to User C
To actually use such a value, we can imagine a DNS-like system which resolves names by looking up the latest IP address from the blockchain; in the same way that an ATM displays our current balance by looking at the credits/debits in the account. All of this can also be cached, of course; provided we either trust the cache to provide the right value, or that we don't care enough about the value to verify it ourselves (eg. transactions between third parties which do not affect us).