We had a total of 265 surveys completed. Note that some questions were mandatory, others were allowed to be left blank or unanswered and others allowed multiple answers. When multiple answers were permitted, the total number of responses for that question is shown.

The general summary is that most respondents were individual developers with 2 or more years of add-on development experience. Natually, they felt comfortable with JavaScript and XUL. They primarily built add-ons for Firefox and hosted them on their own (possibly, in additional to AMO).

These are simply the raw results, we’ll be applying some correlation analysis to draw out more interesting findings and conclusions.

Q1: Which of these best describes your status?

Q2. When did you write your first add-on? (for Firefox or other applications)

Q3. Select the applications (or devices) for which you have created add-ons, 3rd party applications, or plugins.

Q4. How many distinct add-ons have you created? (for Firefox or other applications)

Q5. Was the functionality of your Firefox add-on similar to your add-on for other applications?

Q6. If you have ever started to develop an add-on and then aborted the project, what were the primary factors in your decision to stop development?

Q7. What tool(s) did you use to develop your add-on(s) (for Firefox or other applications) ?

Q8. What tools would help you develop more efficiently?

Q9. How would you rate the ease of development of Firefox add-ons?

Q10. How would you rate Mozilla’s developer documentation?

Q11. How familiar are you with JavaScript and XUL?

Q12-Q14. What were the top three challenging aspects of building your add-on?

Q15. Where do you host your add-on?

Some add-on authors have erroneously used “3.0″ as their maxVersion so when users with these add-ons upgrade from Firefox 3.0 to Firefox 3.0.1, the add-on gets disabled. We encourage these add-on authors to use “3.0.*” as their maxVersion.

We have verified that the majority of add-ons hosted on AMO with Firefox 3 support have “3.0.*” in their compatibility range but there are many sites from where add-ons can be acquired.

First some facts and figures to help set the context and scale for Firefox add-ons.

• There are more than 180 million active monthly Firefox users (more than 60 million daily)
• There have been more than 800 million add-on downloads since the inception of AMO
• There are about 150 million active daily add-ons (Each add-on downloaded from AMO pings once a day)
• AMO hosts about 5600 add-ons and 800 themes
• We believe that there is a sizable number of add-ons not hosted on AMO (more than 1000?)
• The AMO site has about 4-5 million page views and more than 750,000 user sessions daily
• Every day 10-20 blog/news articles are published reviewing or mentioning some Firefox add-ons

Basically, there is a TON of user and developer activity here.

Why are add-ons important?

• They are core to the Mozilla’s mission to offer “choice & innovation”
• Customization is a key differentiator for Firefox. Huge momentum versus Internet Explorer, Safari (no official site), and Opera
• Add-ons have become a platform for innovation and experimentation and it’s relatively easy to get started
• Many startups have made their bet with the Firefox user base as the entry point
• Major web properties invest in building & distributing add-ons
• We believe that Firefox users who have installed add-ons tend to be more loyal

AMO’s Core Principles

Given the above, the AMO site’s function is to present end users with add-ons, keep them up to date and support the developers who publish these add-ons. The AMO development team focuses its efforts around four main guiding principles:

• Help users find and discover add‑ons in their local language
• Ensure the highest quality for what gets published
• Create a satisfied ecosystem of add-on developers, editors and translators
• Create the most comprehensive add-ons directory on the web

In my next posts, we’ll explore the various constituents (End Users, Developers, Translators & AMO Editors) that make up the add-ons ecosystem and their unique needs.

(Note: we should recognize that even though the AMO site only supports official Mozilla products: Firefox, Thunderbird, SeaMonkey and Sunbird. To look at the entire ecosystem, we need to examine the many XUL-based applications and their support for add-ons. Many applications have their own dedicated add-on site such as the ones for Flock, Songbird, eMusic, and Komodo.)

What this means for you as an add-on author is that after you test with the Firefox 3 release candidates, you can use the Developer Tools section on AMO to bump your version number without having to upload a new version of your add-on.

For completeness, if you want to support Firefox (and none of the alpha’s, betas and pre-releases), here are the recommended version ranges (minVersion – maxVersion) to use:

• Firefox 2: 2.0 – 2.0.0.*
• Firefox 3: 3.0 – 3.0.* (Note: that with Firefox 3, it’s a three part version number)

Prior to AMO v3.2, a single list of add-ons was maintained that showcased a sample of what can be done with add-ons. This came to be known as the “Recommended List”. Participation in the recommended list was coveted by authors since it was one of the more visited pages on the site and meant your add-on got downloaded more. AMO currently receives about 5 million pageviews per day with approximately 3% of the traffic to the recommended list. The list has grown and changed over time but has had about 25 add-ons on it. With a single list, the members of the recommended list got the most attention and “starved out” visibility for other add-ons.

One of the changes that was introduced with the latest AMO redesign is the ability to highlight a wider variety of add-ons. Instead of a single list, recommendations are now on a per-application, per-category and a per-locale basis. This gives the community greater flexibility and  increases the face time and exposure (impressions) that an add-on can have.

With AMO 3.2, we now have many lists.

• Category-Recommended lists are edited lists managed by the AMO editors. They represent a list of the most interesting add-ons for a particular category.
• Category-Recommended add-ons appear on:
  • One of the two slots in the AMO category landing page (see sample)
  • The Recommended List page for that category (see sample)
  • The default view in the “Get Add-Ons” panel in the Firefox 3 Add-Ons Manager (once this bug is fixed).
• We anticipate about 5-10 recommended add-ons per category. (Fuzzy math: 14 categories x 10 add-on/category = 140 recommended. Approximately 5000 add-ons on AMO means 3% are recommended.)
• As AMO editors are constantly reviewing add-ons, they can opt to showcase promising add-ons
• Add-on authors can request to become recommended (see last question)

• The Featured list is an edited list managed by the AMO administrators and editors that showcases add-ons for a period of time. This list will have add-ons rotate into and out of it on a periodic basis. Currently, once every 3-4 weeks. The list will be chosen from the existing set of Category-Recommended add-ons.
  • Members of the Featured list will be rotated into one of three slots on the front page of AMO
  • In order to ensure that the feature list maintains a wide sampling of add-ons from various categories, not all add-ons will be swapped out since some categories will need representation.
  • We anticipate about 20-30ish add-ons to be on the featured list at any one time
  • Currently, the following add-on categories will not be chosen for participation in the Featured list: Web Development, Language Tools & Toolbars. This may be revisited at a later date.

So, check out the new AMO site and the latest batch of Category-Recommended add-ons as well as the most recent rotation of Featured add-ons.

We’ve tried to outline a policy around how all this will be managed – if you’d like to read and review the gory details on how the featured and recommend lists work – check this out. Feedback is appreciated as we are trying to be as transparent as possible. There’s more to do in this area including clarifying some edge cases on policy, considering whether to recommend themes and building locale-specific Category-Recommended and Featured lists.