What all this is about?

Where the eternal dilemma and the reasoning between Classified Ads and Ads Listings, there's a need for the two types of advertising, as always has been. Now, in the digital age, we blur that line even further, because most online sites mix a little of both together, creating new ads or marketing models.
Both classified ads and listings have long histories. Classified ads date back to the early 1700s. Newspapers used them as a cheap way to advertise. Originally, classified ads had categories. But they were only for job and real estate listings or for services. They would later change to include more ads, like product listings and personal items.
Listings are those that bloomed with the rise of directories and business listings. Such listings are more organized and structured. A business would provide all the details about its products or services. Another major difference is that classifieds are less organized than listings. Classifieds cover many subjects, while listings are specific and usually categorized. Also, classifieds are for short-term ads. Listings are for long-term ones and can be reused indefinitely.
These two advertising types are also, maybe unconsciously, reflected in the nostr protocol. They both coexist and support each other depending on how the user uses them. NIP-99 standardizes listing implementations in the Nostr protocol. In common terms, we could define them as Ads. The name "Classified Listings" suggests a classification. But, the listings are not structured. They just organize simple data, sharing info about products, services, events, and any other stuff users want to advertise.

The key difference between Classified Ads (NIP-15) and Ads Listings (NIP-99)

NIP-99, on the other hand, focuses on classified ads. The name "Nostr Marketplace" is generic and maybe confusing. But, it's more structured than listings and covers different topics and use cases. This NIP adds rules for making and sharing classified ads. It covers the default title, description, and images. It also covers the merchant, stall, currency, and shipping details.
The naming is confusing. Neither NIP offers a way to classify products and services in their specs. The only way nostr offer some type of categorization or classification is through the t-tag, or more commonly known as #hasgtag. Include few keywords in your Listing (NIP-99) or Classified (NIP-15) Ads. It will help your item be found in the vast sea of data.
Both NIP-15 and NIP-99 standardize listings and ads in Nostr. They let users create ads, products, or services that use the Nostr protocol to share and manage this info. This new approach let a lot of freedom to clients and apps to chose how and what to display for their users. In the nostr ecosystem, we see some cases. For example, Shopstr, Cypher.Space, and Coracle target Listing Ads (NIP-99). Plebian.Market and LNbits Marketplace aim to simplify managing classified ads (NIP-15). Each of these platforms are focusing on a specific NIP, but is that the right approach? What if, instead, we let the user decide how to use them based on their needs?

The Future of Advertising and How Nostr Could Redefine Classifieds and Listings

Imagine a generic clinet that instead limiting what the user suppose to publish, just provide an interface to introduce data. Depending on the user's data, the client could define and publish the contents on multiple NIPs at once, instantly and simultaneously. Or in a near future, on a scheduled and more structured way.
In the ~AGORA, we discussed a nostr integration. We want to crosspost future Ads-posts on nostr, as SN does for discussion-type posts. This NIP ambiguity has not been helping, and that's why hope this post provide a bit more clarity.