# The Web is Still Small After More Than a Decade

arXiv: https://arxiv.org/abs/2004.04623 · HTML: https://mlsanity.com/paper/2004.04623/

## Key facts

- Cited by 1 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 9 Apr 2020.

## Built on by (most cited first, 1 of 1)

- [Augmenting Rule-based DNS Censorship Detection at Scale with Machine Learning](https://mlsanity.com/paper/2302.02031/) (2023)

## Abstract (arXiv)

Understanding web co-location is essential for various reasons. For instance, it can help one to assess the collateral damage that denial-of-service attacks or IP-based blocking can cause to the availability of co-located web sites. However, it has been more than a decade since the first study was conducted in 2007. The Internet infrastructure has changed drastically since then, necessitating a renewed study to comprehend the nature of web co-location. In this paper, we conduct an empirical study to revisit web co-location using datasets collected from active DNS measurements. Our results show that the web is still small and centralized to a handful of hosting providers. More specifically, we find that more than 60% of web sites are co-located with at least ten other web sites---a group comprising less popular web sites. In contrast, 17.5% of mostly popular web sites are served from their own servers. Although a high degree of web co-location could make co-hosted sites vulnerable to DoS attacks, our findings show that it is an increasing trend to co-host many web sites and serve them from well-provisioned content delivery networks (CDN) of major providers that provide advanced DoS protection benefits. Regardless of the high degree of web co-location, our analyses of popular block lists indicate that IP-based blocking does not cause severe collateral damage as previously thought.