Updated: Dec 23, 2020
To determine relevance, search engines use algorithms, a process or formula by which stored information is retrieved and ordered in meaningful ways. These algorithms have gone through many changes over the years in order to improve the quality of search results. Google, for example, makes algorithm adjustments every day — some of these updates are minor quality tweaks, whereas others are core/broad algorithm updates deployed to tackle a specific issue, like Penguin to tackle link spam. Check out our Google Algorithm Change History for a list of both confirmed and unconfirmed Google updates going back to the year 2000.
Why does the algorithm change so often? Is Google just trying to keep us on our toes? While Google doesn’t always reveal specifics as to why they do what they do, we do know that Google’s aim when making algorithm adjustments is to improve overall search quality. That’s why, in response to algorithm update questions, Google will answer with something along the lines of: "We’re making quality updates all the time." This indicates that, if your site suffered after an algorithm adjustment, compare it against Google’s Quality Guidelines or Search Quality Rater Guidelines, both are very telling in terms of what search engines want.
Comments and Internal links are important: Links have historically played a big role in SEO. Very early on, search engines needed help figuring out which URLs were more trustworthy than others to help them determine how to rank search results. Calculating the number of links pointing to any given site helped them do this.
Backlinks work very similarly to real-life WoM (Word-of-Mouth) referrals. Let’s take a hypothetical coffee shop, Jenny’s Coffee, as an example:
Referrals from others = good sign of authority
Example: Many different people have all told you that Jenny’s Coffee is the best in town
Referrals from yourself = biased, so not a good sign of authority
Example: Jenny claims that Jenny’s Coffee is the best in town
Referrals from irrelevant or low-quality sources = not a good sign of authority and could even get you flagged for spam
Example: Jenny paid to have people who have never visited her coffee shop tell others how good it is.
No referrals = unclear authority
Example: Jenny’s Coffee might be good, but you’ve been unable to find anyone who has an opinion so you can’t be sure.
This is why PageRank was created. PageRank (part of Google's core algorithm) is a link analysis algorithm named after one of Google's founders, Larry Page. PageRank estimates the importance of a web page by measuring the quality and quantity of links pointing to it. The assumption is that the more relevant, important, and trustworthy a web page is, the more links it will have earned.
The more natural backlinks you have from high-authority (trusted) websites, the better your odds are to rank higher within search results.
Do you have clean information architecture?
Information architecture is the practice of organizing and labeling content on a website to improve efficiency and findability for users. The best information architecture is intuitive, meaning that users shouldn't have to think very hard to flow through your website or to find something.