Harness Content Portability to Enrich Apps

With the Internet as a great repository of web apps, you need not develop a new app each time you plan to provide a feature on your portal. Here are some alternatives

Monday, December 01, 2008

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You've got a great idea for a new application, on the web or on the desktop, and you're starting to think about the various features and functionality it will provide. More than likely, a big part of your idea is original, but various features you want to implement already exist out on the web as part of another website. For instance, perhaps you want to create a new web application called Develevent, a site where developers can find technology events around the world and get all the information they need to plan their trips to those events. At its core, this web-application should have the basic functionality of listing details about a given event and searching for events. Additionally, for any given event, you may also want to incorporate features that show the user hotels that are available for the nights around the event dates, flights to the nearest airport from the user's home airport, historical weather information for the city of the event at the given time of year, and so on. These features will be valuable to your users, but it is not your core business, nor is it truly feasible to become a hotel availability aggregator or a historical weather data storehouse.

Luckily for you, the web is rich with companies and websites whose core business it already is to provide such functionality. As users of the web, we often see these sites as silos, where in order to access their content, it is necessary to visit the site itself. However, with open APIs, RSS feeds, and services like Dapper and Yahoo! Pipes, it is becoming easier and more feasible for developers to incorporate content and functionality from existing websites into their new creations while focusing on the core functionality you are best suited to provide. With affiliate networks such as Commission Junction, you can even earn money when your users engage with and purchase from the sites whose content and functionality you are incorporating into your own.

Let's take a deeper look at the various means to obtain content you could incorporate into your new application.

Look for APIs
If a website whose content you want to use has an API (Application Programming Interface), this is your best bet. APIs give you structured access to a website's content and allow you to programmatically replicate certain functionality. For instance, Amazon provides many APIs including one that allows you to search for albums by a specific artist and filter and sort the results by various criteria, such as number of ratings and release date. This allows you to easily incorporate Amazon's content and functionality directly into your application. For more about Amazon's web services, check out http://tinyurl.com/2xyfhj.

RSS/Atom feeds
If an API is not available, you may be able to use an RSS feed. Most websites offer RSS feeds for their content. The biggest drawback to RSS feeds (as opposed to APIs) is that they are usually used to provide a website's latest content in date-order. Often times, there is no RSS feed that allows you to pass a parameter, such as a search term or an argument indicating how to sort the results. For example, a hotel site may provide an RSS feed of its best deals this week, but you cannot tell it to give you hotel availability in a specific city on a specific date. However, if a site does have an RSS feed with the content you need, this is a good and easy solution.

Expedia is a good example of a site that provides excellent RSS feeds with parameterization. Check out their RSS feeds here: http://tinyurl.com/5wtjlb. For an example of a feed of New York, see here: http://tinyurl.com/5cm4ph.

What about a site that doesn't have a good feed? Or doesn't have one at all?
If you find yourself wanting to use content and functionality from a website that doesn't provide an API or a feed, or whose web services don't meet your needs, you still have some choices. First of all, many sites do have APIs that they do not expose except to their partners. There are others that provide them to affiliate networks, so joining such a network will give you access.

Parsing & Storing/Crawling
APIs are accessed by programmatically calling a URL and downloading the results given back. Generally the returned content of an API is XML or JSON. RSS and Atom feeds are in XML. This allows you, as a developer, to easily parse the content and do what you want with it. Depending on your application, there are a few ways in which you can access and work with this structured content.

One common method is to access and parse the content on the fly as the result of a user action. For example, let's say you provide a feature that allows your users to search for hotels in a specific city. When the user provides the city and dates of interest, your code would access the APIs of one or more hotel sites, passing the city and dates, to get availability, parse the returned results, and display them to the user immediately. This approach is most useful when you need very fresh data and when you cannot anticipate the values your users are going to search for. The downsides to this method are that there is latency associated with accessing the API (ie, your user must wait) and your site causes a lot of traffic on the API of the remote website. Also, if the remote site goes down, your users will not have access to this feature.

To address the downsides of the on-the-fly method, as well as to allow greater flexibility with how you filter, sort, and modify the returned data, your code can access the content from an API 'offline.' This means that you have some process that runs regularly (not as a result of some user's action) to download the data from a website's API or feed and then store it for access later. The most common place to store such data is in a database (like MySQL) or a search engine (like Lucene/Solr), but you could even store the XML files directly on disk and access them locally.

Earning money
Regardless of whether you choose to build your website as a business or just a personal project, it never hurts to earn a little revenue from your efforts. While you're unlikely to generate a lot of revenue unless your application is heavily used, it can still be valuable to integrate with 'affiliate programs' of websites whose content you are using. Most websites that sell directly to consumers participate in affiliate programs. These programs share revenue with application developers who send consumers to their site when those consumers make a purchase. So, for instance, if you incorporate a feature into your application that allows users to search for hotels and a user subsequently books a hotel that you sent them to, then you could receive a commission on the sale.

Affiliate networks work by providing you with an 'affiliate ID' which you then pass as an argument in the URL when you send a user to the website selling a product. The network tracks any sales from that user and associate the revenue share with your affiliate account. Revenue share can range from pennies to large sums depending on the type of item and size of sale.

Legal issues
Whenever you work with someone else's content, you should be aware of any legal implications that your actions may have. Regardless of the method you use to obtain the content, make sure you refer to the website's terms of use. Unless explicitly stated otherwise in the terms of use, you will need the direct permission of the website owner to use his or her content.

Conclusion
As a developer, you have the entire web at your disposal when building your applications. By harnessing the content and functionality already available on the web, you can focus on what you do best while still providing many rich features. The websites whose content you use will benefit by being exposed to a wider audience and your users' experience will be enriched.

Jon Aizen, co-founder and CTO, Dapper

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