Shipping Default Domains

Firefox for Mobile (Android and iOS) ships sets of default content in order to improve the first-run experience. There are two primary places where default sets of domains are used: URLBar domain auto-completion, and Top Sites suggested thumbnails.

The source of these domains is typically the Alexa top sites lists, global and by-country. Before shipping the sets of domains, the lists are sanitized.

Domain Auto-completion

As you type in the URLBar, Firefox will scan your history and auto-complete previously visited domains that match what you have entered. This can make navigating to web sites faster because it can avoid significant amounts of typing. During your first few uses, Firefox does not have any history and you are forced to type full URLs. Shipping a set of top domains provides a fallback.

The top domains list can be localized, but Firefox will fallback to using en-US as the default for all locales that do not provide a specific set. The list can have several hundred domains, but due to size concerns, is usually capped to five hundred or less.

Sanitizing Methods

After getting a source list, e.g. Alexa top global sites, we apply some simple guidelines to the list of domains:

  • Remove any sites in the Alexa adult site list.
  • Remove any locale-specific domain duplicates. We assume primary URLs (.com) will redirect to the correct locale (.co.jp) at run-time.
  • Remove any explicit adult content* domains.
  • Remove any sites that use explicit or adult advertising*.
  • Remove any URL shorteners and redirecters.
  • Remove any content/CDN domains. Some sites use separate domains to store images and other static content.
  • Remove any sites primarily used for advertising or management of advertising.
  • Remove any sites that fail to load in mobile browsers.
  • Remove any time/date specific sites that may have appeared on the list due to seasonal spikes.

Suggested Sites

Suggested sites are default thumbnails, displayed on the Top Sites home panel. A suggested site consists of a title, thumbnail image, background color and URL. Multiple images are usually required to handle the variety of device DPIs.

Suggested sites can be localized, but Firefox will fallback to using en-US as the default for all locales that do not provide a specific set. The list is usually small, with perhaps fewer than ten sites.

Sanitizing Methods

After getting a source list, e.g. Alexa top global sites, we apply some simple guidelines to the list of domains:

  • Remove pure search engines. We handle search engines differently and don’t consider them to be suggested sites.
  • Remove any locale-specific domain duplicates. We assume primary URLs (.com) will redirect to the correct locale (.co.jp) at run-time.
  • Remove any explicit adult content domains.
  • Remove any sites that use explicit or adult advertising.
  • Remove any URL shorteners and redirecters.
  • Remove any content/CDN domains. Some sites use separate domains to store images and other static content.
  • Remove any site that routinely publish fake or misleading content.
  • Remove any site that degrades, intimidates, incites violence against, or encourages prejudicial action against someone or a group based on age, gender, race, ethnicity, national origin, religion, sexual orientation, disability, religion, geographic location or other protected category or constitutes hate speech.
  • Remove any site that harms users such as by using viruses, spyware or malware, worms, trojan horses, time bombs or any other such malicious codes or instructions.

Guidelines for Adult Content

Generally the Adult category includes sites whose dominant theme is either:

  • To appeal to the prurient interest in sex without any serious literary, artistic, political, or scientific value
  • The depiction or description of nudity, including sexual or excretory activities or organs in a lascivious way
  • The depiction or description of sexually explicit conduct in a lascivious way (e.g. for entertainment purposes)

For a more complete definition and guidelines of adult content, use the full DMOZ guidelines at http://www.dmoz.org/docs/en/guidelines/adult/general.html.

Updating Lists

After approximately every two releases, Product (with Legal) will review current lists and sanitizing methods, and update the lists accordingly.