If someone told you that they aggregate things and someone else told you that they curate things, would you know the difference?
In the travel business, these two ways of distributing products and services to travelers are quite different.
The problem is that travelers are generally unaware of the difference and, as a result, don't understand what they are getting when they look for experiences through a curator or an aggregator.
Let's first define the terms. According to Oxford, the term "aggregate" means:

verb /agrigayt/ combine into a whole.
The term "curate" means:

verb select, organize, and look after the items in (a collection or exhibition).
Already you can see that the verbs mean entirely different things. Aggregation implies combining a variety of objects to create a whole, whereas curation implies selection, organization, and care.
In the travel business, aggregation is very much the combining of distinct sources of product and delivering it as a single unified list of products from which the traveler can choose the best product for their needs.
In the case of airlines and hotels, this would be done using a combination of direct connects and GDS connections. When a traveler searches for a given location and time of year, the system scours through the various sources for the best matches and displays the results.
The system makes no judgments on the quality or appropriateness of the product but rather provides an unbiased (or so it would seem) list of matching results. In the case of the aggregator, the accountability of the product or service delivered is usually left to the supplier who actually provides the service since, in most cases, the aggregator will make it clear that they do not take responsibility for the deliver of the service.
Curation is a very different approach to delivering products to consumers. Although there may be an aggregation component to the curation process, primarly for the purposes of sourcing the products for curation, the curator is then responsible for selecting the products that they feel are the best fit for their customers, organizing them, and maintaining them in the collection.
When a traveler searches for experiences from a curated source, they are relying on the experience and expertise of the curator to ensure quality, viability, and credibility of the source.
In the case of curation, the customer may not even know the source until after the booking is made relying entirely on the reputation of the curator. It's a little bit like the old saying "Any friend of Jim, is a friend of mine".
To the traveler, it may be difficult to know whether a travel site is an aggregator or a curator just by looking at it. One way, I have found is to look at their tag line or mission statement and see if they fall into either of these criteria:
- The site is most likely an aggregator if it claims to have the largest number of sources (ie. hotels, flights, car, whatever), promotes the number of locations or properties/flights (ie. 50,000+ hotels), and offers customer reviews but does not provide it's own reviews/editorial. Many online agencies and metasearch sites like Expedia, Travelocity, and Kayak would fall into this classification.
- The site is most likely a curator if it claims the best selection of products from reputable sources, promotes the quality of the products over the quantity, offers a combination of customer reviews and editorial, and manages & updates the source content directly. Many experiential travel sites like Viator, isango!, Kijubi, Expedia's Activities/Attractions, TravelDragon, and others would fall into this category. The reason why most of these sites curate is partly because aggregation of content for experiential product is almost impossible given the lack of standard distribution standards and systems. Curation does occur in other more traditional segments such as hotels. The Mr & Mrs Smith site, for example, would be considered a curation site for selected boutique hotels.
In the end, the two methods for distribution offer their own benefits. Aggregation will most likely offer the most number of choices and require the consumer to filter and sort based on their preferences.
Curation, on the other hand, will provide a fewer number of choices defined by the curator's preferences and presented as a collection. Both options are valid and serve consumers in different ways.
How effective the two options are depends a lot on the reputation of the brand and the trust the consumer has with the site. In the end, both approaches provide consumers with choice and that is never a bad thing.
Pic: Espos.de on Flickr and Shopkitson.