What will happen to the search results if I merge two domains onto one website?

If you implement 301 redirects from one domain to another, you will have one domain displayed in the output and another domain shown in the search results.

It is highly likely (99.9%) that if you set up two identical websites hosted on different domains, promoting them in the same region or city, with the same content, text, and under the same Certificate Authority (CA), sanctions for affiliation will be imposed. This can result in the loss of all your achieved positions and traffic.

It's important to note that affiliate sites are typically owned by the same company and share several characteristics, such as being promoted using the same list of search queries, hosted on the same hosting, having common Whois data for both domains, similar topics, address and company name, IP addresses, among others (approximately 25 indicators).

Therefore, setting up identical sites on different domains and promoting them in a way that suggests affiliation can lead to severe consequences in terms of search engine rankings and visibility. It is crucial to comply with search engine guidelines and ensure that your websites provide unique value and differentiation.

By directing multiple domains to the same directory where the website files are stored, search engines will recognize these domains as affiliates and will remove one of them from the search results.

It's crucial to realize that even if you place the website files in separate locations, such as different hosting sites, search engines still evaluate the content parameters to identify domain associations. Consequently, they will only display one domain for relevant queries.

Therefore, it is important to avoid setting up multiple domains pointing to the same directory if you want each domain to have independent visibility in search engine results. Search engines prioritize unique and distinct content, and affiliations between domains can lead to penalties and loss of visibility.

It is recommended to focus on developing a single domain with high-quality content that provides value to users, rather than trying to manipulate search engine rankings by creating multiple affiliated domains. Building a strong online presence through ethical means will yield better long-term results.

By merging domains, you'll essentially be transferring the authority and ranking signals from one domain to the other. This process can be advantageous if you're consolidating a lower-ranking domain onto a more authoritative one, as the stronger domain's ranking signals can help boost the visibility of the combined content.

However, if you're merging a more authoritative domain onto a less established one, you risk losing some of the ranking power and visibility that the stronger domain previously enjoyed. Search engines like Google may perceive the merged website as a new entity, resulting in a temporary dip in rankings until the new site can re-establish its authority.

Additionally, you'll need to carefully plan and execute the domain merger to ensure that all existing links, both internal and external, are properly redirected to the new URL structure. Failing to implement proper 301 redirects can lead to broken links, which can negatively impact your search engine rankings and user experience.

It's also crucial to analyze the existing content on both domains to identify any potential duplication or overlap. Search engines penalize websites for duplicated content, so it's essential to consolidate and de-duplicate any overlapping content during the merger process.

From a technical standpoint, you'll need to ensure that the website's infrastructure, including the hosting environment, server configurations, and database structures, can handle the increased load and traffic resulting from the merged domains. Performance issues and slow loading times can negatively impact both user experience and search engine rankings.

Additionally, you'll need to update all external references to the merged domains, such as listings in directories, social media profiles, and any other online presence. Failing to update these references can lead to confusion and potentially lost traffic.

In terms of branding and marketing, merging domains may require a strategic communication plan to inform your audience and stakeholders about the changes. This can include updating marketing materials, email signatures, and other branded assets to reflect the new domain.
Merging domains onto a single website can have significant implications for search engine optimization and website visibility. While it can potentially consolidate authority and ranking signals, it also carries risks of losing existing visibility if not executed properly. Careful planning, technical implementation, and a strategic communication plan are crucial to ensure a successful domain merger.