Suppose the code and markup on one old-school web page weighs in at 60K. Say that, by replacing outdated <font> tags and other presentational and proprietary junk with clean, structural markup and a few CSS rules, that same page can weigh 30K. (In my agency's practice, we can often replace 60K of markup with 22K or less. But let's go with this more conservative figure, which represents bandwidth savings of 50%.) Consider two typical scenarios, detailed next.
Scenario: A self-hosted small business or public sector website serves a constant stream of visitors—several hundred at any given moment. After cutting its page weight in half by converting from presentational markup to lean, clean, structural XHTML, the organization saves $1,500 a month.