[9] This approach consolidated a school of web design that favoured visually oriented aesthetics over ideals of usability as championed by Jakob Nielsen.
[10] In the absence of browser support for the still gestating Cascading Style Sheets (CSS) presentation language (which he influenced and encouraged), he recommended the use of invisible single-pixel GIFs as spacers for visual control, and table-based layouts.
[11] Siegel reconsidered these recommendations in 1997, denouncing the single-pixel GIF and table-based layouts as ‘hacks’ and expressing optimism that advances in CSS support were going to bridge the divide between structure and presentation.
In 2010 Siegel's fourth book came out, Pull,[16] which discusses the impact of the Semantic Web, defined in unusually broad terms,[17] on business.
In recent years, Siegel has been pursuing the project of an open-source platform named Pillar, which would enable users to retain control of their personal information using the blockchain.