Having a large content-rich website makes life a lot easier when it comes to SEO. Particularly if you’re trying to rank well in Google for a range of different keywords. APIs (Application Programming Interfaces) to the rescue! “Mash up” multiple APIs together and voila! — unique content. HousingMaps was one of the first and most notable mash-ups. What can you mix-and-match to make into a deep site full of keyword-rich useful content? Start your journey by consulting ProgrammableWeb’s APIs list. This list is famous among programmers.

Anybody who’s into APIs will know the site Programmable Web. I had the pleasure of attending the session about APIs presented by John at Programmable Web last week at the Web 2.0 Expo.

Here are my notes from John’s session:

ProgrammableWeb.com
Site launched in Summmer 2005.
APIs, mashups and tools directory
News, community, reference materials
400 APIs and 1800 mashups

Why bother with APIs?
Make money: eBay over 45% of all products get listed via their APIs. 3 billion API calls per month.
Save money: Smugmug saves $500k year with Amazon S3 storage.
Build brand: Google Maps 300% growth vs 20% Mapquest
Build empires: Salesforce.com – over 50% of all transactions via their API. 500 apps so far.
Innovate: 100’s of Flickr apps. Is Twitter next?

What makes an API successful?
Rule #1, the underlying service: or, a good API on a bad service is like lipstick on a pig
A plan and a business model
Simple, open, easily adopted
Providing choices
Good developer support

Number of API providers in each of the top 10 categories:
Geo/mapping 38%
Reference 26%
Internet 21%
Search 18%
Shopping 18%
Music 17%
Photos 14%
Messaging 14%
Bookmarks 10 %
Widgets 10%

Unexpected sources of APIs:
HOTorNOT
U.S. postal service
Weatherbug
Betfair
Theholybible
Secondlife
theworkforyou
Sunlight

API Business Models

Who	What	How
Amazon ECS	retail	affiliate model
Amazon.com	infrastructure	pay-as-you-go
eBay	auctions	APIs for listings
Salesforce.com	CRM	“seats”
Exact Target	bulk email	tiered pricing (they do millions of API transactions per quarter)
Cypress Golf	ASP for reserving tee times	integration
Rhapsody	music	partnerships

Best practice is to bake your business model into your API

API pricing & licensing models

Revenue sharing	via affiliates; advertising (see new AdSense API)
Subscription	per time period; classic Software as a Service
Tiered	pricing in volume buckets
Per-call metering	fee per API call (see strikeiron)
Utility	API is free, but fee for resources (cpu, storage, bandwidth)
Pay per conversion or sign-up	commissions and referrals (yahoo mail)
Ad-supported is free, ad-free is premium	see ad and branding-free premium mapping
Units	different calls priced at different levels (google AdWords API)

APIs as bizdev (business development) enabler
decentralized business development
an API can lower barriers to working with you
consumer/hacker –> business/partner, e.g. Zazzle, Englaze, Qoop, Moo (we love to print)

Design
design for people & computers

Technology: the big debates
protocols – REST vs SOAP

Top 5 API protocols & styles
1. rest 68%
2. soap 40%
3. javascript 7%
4. xml-rpc 6%
5. APP (atom publishing protocol), Google gdata 3%
specialized or proprietary (xmpp, sms, saml, skype, oscar)
(20% support more than 1 of these protocols)

REST vs SOAP – pros vs. cons

Protocol	Pros	Cons
SOAP	established standard, wide tool support	complexity, interoperability issues
REST	simplicity, built on how the web works (URIs and core HTTP methods)	lack of standards, tool support challenges

Comparing protocol choices
77 APIs from 6 providers:

	rest	soap	xml-rpc	javascript	other
google	11	3	1	4	3
amazon	8	10
microsoft	1	6	1	3	1
ebay	2	2			1
yahoo	19	1		3	2
aol	3	1	2	2	4

favor simple designs
use more than one to broaden your base
be as consistent as possible

Data formats supported: 2 dozen
xml, json, rss, atom, yaml, icalendar, csv, serialized php, html, pn, georss, vcard, text, rdf, opml, vml, tv-anytime, hcalendar, xspf, sql, gml, cdf
favor simplicity and standards
use more than one to broaden your base
provide domain-appropriate alternatives
25% of new apis listed at Programmable Web in 2007 support json
8% of all apis listed before 2007 supported json

xml: well established, general purpose; greater parsing overhead; well suited for documents; wide tool support
json: objects and simple types; fast parsing, good fit for client side scripting; bindings for 20+ languages

Yahoo Mail added json support in 2 days

John’s favorite APIs are from Flickr

#1 api provider issue is adoption
How many steps from zero-to-code? Easy sign up and self service is key. Offer a free level of API use.
How well do you treat your developers? Developer network and evangelism
How’s your pre-code support? Docs, gallery, forums, mailing lists, and lots of code. Media: videos, screencasts, podcasts
Any post-code support? Certification, marketing, events. System status (trust.salesforce.com shows availability of all their API servers), usage reporting

Know the tools ecosystem:
Data mashup tools – yahoo pipes, grazr, rssbus, data mashups
Scraping tools – kapow, dapper
Visual development tools – jackbe, qedwiki, proto, teqlo, bungee labs
DIY consumer tools – platial, google my maps, map builder

Risks and issues
Dependencies: business and technical. Strategize accordingly – go in eyes-open. Mashups: know switching costs (consider tools like Mapstraction)
Lack of service level agreements. Consider commercial license models (ex google maps enterprise). Mashups: should also disclaim warranty (“trickle-down terms”)
Commercial vs. non-commercial use. Most API terms of service differentiate these, but vaguely. If you place ads on your mashup, is that “commercial use”?
Copyright law issues. What data can be remixed and how? See: Flickr API integrates Creative Commons license.

The big issue: identity
Where are the ‘personal mashups’? high-value data locked behind IDs and password
Limited standardization & consensus. Even in new competing “authorization APIs”. Yahoo! bbauth, microsoft liveid, google web auth
Solutions: OpenID? Meta-identity networks? TBD

Privacy issues. Beware.
Data mining 101: e.g. finding subversives by mining Amazon wishlists for readers of “1984”

Trends
Battle of the platform players
Having an API as a checklist item. Got an API? Check.
Lightweight services & data. rest protocol & json data format
New tools. for developers and non-devs
Enterprise mashups (mashups behind a firewall)
New business models (even more business models will be forthcoming)

Recommendations
Have an API strategy and a plan
Keep it simple: protocols, formats, tools, adoption
Provide choices: in order to reach the widest base
Treat developers well: and they will treat you well in return