A disadvantage of digital advertising is the large amount of competing goods and services that are also using the same digital marketing strategies. For example, when someone searches for a specific product from a specific company online, if a similar company uses targeted advertising online then they can appear on the customer's home page, allowing the customer to look at alternative options for a cheaper price or better quality of the same product or a quicker way of finding what they want online.
In some contexts, the term SEM is used exclusively to mean pay per click advertising, particularly in the commercial advertising and marketing communities which have a vested interest in this narrow definition. Such usage excludes the wider search marketing community that is engaged in other forms of SEM such as search engine optimization and search retargeting.
Word of mouth communications and peer-to-peer dialogue often have a greater effect on customers, since they are not sent directly from the company and are therefore not planned. Customers are more likely to trust other customers’ experiences. Examples can be that social media users share food products and meal experiences highlighting certain brands and franchises. This was noted in a study on Instagram, where researchers observed that adolescent Instagram users' posted images of food-related experiences within their social networks, providing free advertising for the products.
In order to engage customers, retailers must shift from a linear marketing approach of one-way communication to a value exchange model of mutual dialogue and benefit-sharing between provider and consumer. Exchanges are more non-linear, free flowing, and both one-to-many or one-on-one. The spread of information and awareness can occur across numerous channels, such as the blogosphere, YouTube, Facebook, Instagram, Snapchat, Pinterest, and a variety of other platforms. Online communities and social networks allow individuals to easily create content and publicly publish their opinions, experiences, and thoughts and feelings about many topics and products, hyper-accelerating the diffusion of information.