For the US, the entire digital ad market is $83B/yr, which works out to $257 per person per year, or $717 per household. Keep in mind that about half of the country's population is "frequent internet users", so that number is almost certainly an underestimate for anyone who browses HN.
For comparison, this number just recently passed TV advertising, which is about $70B/yr ($217/person, $605/household).
For comparison, this number just recently passed TV advertising, which is about $70B/yr ($217/person, $605/household).