The March Core Update is one of the most significant updates in Google's history, which officially concluded on April 19, 2024. It was aimed at reducing low-quality, unhelpful content and certain types of spam, as well as making updates to various systems. This was part of the dual March Core and March Spam updates. The update was anticipated by the SEO and marketing communities, especially those affected by previous updates such as the September 2023 Helpful Content Update.

Four major trends observed from the March Core Update include:

1. Reddit's SEO traffic and visibility growth: Reddit has seen a surge in organic traffic for many types of queries and categories, partly due to Google's 'Hidden Gems' update which aimed at increasing the visibility of forum and discussion content.

2. Drop in visibility for news and affiliate websites: Many informational sites, including news and media websites that monetize through display ads and affiliate links, saw a significant decline in SEO visibility and traffic.

3. Google's claim of a 45% reduction in unhelpful content: Google aimed to reduce unhelpful content in search by 40% and later reported achieving a 45% reduction. This was partly due to manual actions issued to sites using generative AI to mass-produce content.

4. No relief for Helpful Content Update sites: Sites affected by the September Helpful Content Update did not see traffic recoveries and often faced further declines.

After the March Core Update, Reddit has become a major winner in terms of SEO traffic and visibility. The platform's SEO visibility growth began in the fall of 2023 and continued to increase significantly, with Google often showing multiple sitelinks for Reddit in search results. This growth was tied to Google's announcement of its 'Hidden Gems' update and a partnership with Google, which includes a $60 million annual payment for direct access to Reddit's API. Despite Google's statement that the agreement with Reddit did not include ranking its content higher on Search, Reddit has become a major SEO competitor with a significant surge in rankings across various content types.

News and affiliate websites have experienced a drop in SEO visibility after the March Core Update due to a significant correlation between informational sites whose monetization strategy relies on display ads and/or affiliate links, and traffic drops stemming from the update. This pattern is consistent with a trend affecting these types of sites over the past few years, but the impact has ramped up in recent months. The 'September 2023 Helpful Content Update' also appears to have disproportionately impacted these websites. It's important to note that correlation does not imply causation, and other factors may also contribute to the decline in visibility.

Google's 'site reputation abuse' spam policy is a new type of spam policy violation that was launched after May 5, 2024. This policy targets major sites deemed as abusing their sites' reputation for SEO opportunities. It includes significant manual actions against these sites and is part of Google's continuous efforts to refine search results and reduce unhelpful content. The policy is likely aimed at sites misusing their established credibility to manipulate search rankings, although specific details of the policy have not been confirmed by Google.