Implicit vs Explicit Search: Reviewing The History & Strategic Best Practices

Every few years, significant transformations occur in the search industry, causing disruptions and an occasional sense of panic amongst search practitioners. Over a decade ago, the advent of mobile devices and Google’s mandatory shift to Enhanced Campaigns marked a pivotal moment in the search industry and led to rapid growth as users began conducting more and more searches on their phones. Most recently, the advancement of artificial intelligence (AI) has introduced new automated campaign formats that enable advertisers to reach their audiences across platforms using machine learning data signals rather than keywords to help simplify workflow while creating an omnichannel optimization experience. 

Each evolution over the years has reshaped how advertisers identify and engage with their target audiences during the key moments that matter most. To effectively find and connect with their audience in critical moments, search advertisers must not only comprehend users search queries but also grasp the underlying intent behind those queries. This fundamental distinction is the rationale behind the creation of implicit search. The gradual introduction of implicit search signals into search results and contextual engines has quietly become one of the most significant enhancements in digital advertising over the past decade. 

Despite possessing many of the same attributes as generative AI, implicit search has not garnered the same level of attention. Consequently, we are writing this piece today to provide this critical search enhancement with the necessary spotlight and recognition it deserves. 

Defining Implicit Search 

To dive a little deeper, Implicit search technology assists in generating the most pertinent user experience when there is ambiguity in a user’s search query. It employs factors such as location, search history, and online behavior to determine the most relevant results. Unlike explicit searches, implicit searches rely on surrounding or contextual information to provide the most applicable outcomes. 

A notable example of implicit search technology is Google Instant, which was launched in 2010. Prior to Google Instant, users typed in a query and pressed Enter to view results the old-fashioned way. Google Instant however, leveraged implicit search signals to dynamically update search results in real time as users typed their queries. For instance, a user typing “ball” might initially see results for “ball game,” but as they continue to type, the results would transition to more refined queries such as “balloon artist near me.” 

Over time, Google’s algorithms have progressively enhanced their ability to comprehend a user’s intent by incorporating factors such as search history and location to populate pertinent queries and outcomes. Consequently, Google’s advertisers no longer require keyword targeting, as Google’s AI can seamlessly align a user’s query with the advertiser’s paid ad that most closely corresponds to their needs. 

Contextual Search: The Next Evolution of Implicit Signals for Advertisers 

This same technology underpins the burgeoning contextual search marketplace. Unlike traditional search platforms that rely on signals like search history, contextual search platforms employ language processing models to discern the intent behind an article or piece of content on the open web. Based on the user’s interests and the content they are consuming, implicit contextual search algorithms can recommend a relevant search query that facilitates users in extending their research beyond the current content they are engaged with. This presents an opportunity for advertisers to capitalize on contextual search placements, enabling them to identify high-intent users without the need for explicit search queries. Furthermore, this approach allows advertisers to reach users in environments beyond the search engine. 

In an era where AI summaries and walled gardens reduce opportunities for discovery, implicit search represents a new frontier for connecting people with information. It’s less about waiting for explicit queries and more about presenting relevant experiences at moments of high intent.

Traditional search holds significant value for advertisers because their audience explicitly communicates their interests, and advertisers can simply align their offerings with those interests. However, there is a limitation on the frequency of such matches. Contextual implicit search serves as a crucial complement to traditional search by capitalizing on the same intent signals and identifying the same high-quality audience both in-market and during research beyond the search engine. 

Strategic Gaps and Opportunities 

So why is implicit contextual search not typically considered a separate tactic in advertisers’ media plans? Simply put, Google, Microsoft, and Yahoo have not established a contextual marketplace that provides advertisers with strategic control. They’re implicit search activations are combined in one blended campaign with their explicit counterparts. Therefore, while implicit search is heavily leveraged in each of their search partner networks, advertisers cannot purchase implicit contextual search independently from explicit on these platforms that control most of the search marketplace. 

The major platforms have little incentive to unbundle implicit search; doing so would dilute their paid query models. For performance-minded marketers, this is a gap, but it is also an opportunity to branch out. Independent contextual search providers make implicit intent visible, measurable, actionable and something that can be optimized independently of the traditional explicit experience. 

This is where independent search platforms and contextual marketplaces have carved out a niche by providing advertisers with the control and strategic runway to optimize for the nuances of implicit search behavior. An advertiser’s ability to recognize a user’s true intent and curate the appropriate ad experience significantly impacts the likelihood of driving positive outcomes. Platforms that enable advertisers to make these strategic decisions are becoming increasingly important and impactful.  

Implicit Search is Just What the Doctor Ordered for Health & Rx Advertisers 

In healthcare and pharmaceuticals specifically, implicit search fills the growing gap between curiosity and care. Patients and healthcare professionals rarely type branded drug names or conditions directly into search bars. Privacy, stigma, and regulation limit how they express their intent. However, they spend hours reading, researching, and validating information across trusted medical and lifestyle content. 

Implicit contextual search holds significant value in the pharmaceutical industry. By aligning advertisements with the topics and moments preceding or following explicit searches, pharmaceutical brands can ethically engage with high-intent audiences before competitive saturation in traditional paid search. This approach also provides a compliant and privacy-safe bridge in an era where personal identifiers are diminishing. 

Beyond compliance, implicit search offers pharmaceutical marketers a more valuable asset: contextual trust. In a category where misinformation and consumer skepticism can erode confidence, appearing in medically credible environments reinforces both brand authority and public health literacy. When a reader interacts with an article about “new cholesterol treatments” or “how to talk to your doctor about depression,” the message is not interrupting but rather adding relevance to their moment of curiosity. 

This approach also enables pharmaceutical brands to strike a balance between reach and responsibility. Instead of competing for crowded and expensive branded queries, marketers can reach the same audience at a different stage in their journey when education, awareness, and empathy have the greatest impact. Implicit search bridges the gap between awareness campaigns and point-of-care engagement, transforming passive research into active, informed conversations with healthcare professionals. 

Looking Forward 

Implicit search is not a novel concept, and contextual implicit search is not a new tactic. However, it has not received the attention it deserves compared to other digital advertising strategies. In the future, advertisers should proactively seek avenues to optimize towards implicit search signals and maximize the impact of identifying high-intent users without the need for a search query or high-priced third-party audience targeting. 

Implicit search’s significance has never been more pronounced. As artificial intelligence redefines discovery, and traditional search becomes less transparent, marketers who embrace implicit intent will gain an advantage in terms of earlier, cheaper, and more effective strategies. For pharmaceutical brands, this entails meeting patients and healthcare professionals where their questions arise, not just where they conclude. 

This piece was written by Chris Matuszewski, Pharma Industry Lead – Perform Media