A search signal is a characteristic of a website that a search engine algorithm considers when ranking a website.
Google claims to consider more than 200 separate signals when ranking a site, the most important are generally accepted to be:
- Relevant, Quality Content: Does your page provide relevant information about the search term.
- Quality Back Links: Do other people think you have good content.
- User Experience: Is your website fast and well laid out.
- Mobile Friendliness: Is your website readable and usable on a mobile device.