This was originally written early September. The patch was live late September. And 4 weeks of results later, this post. My apologies if I mixed past and present tense

The number of add-on downloads was always an interesting figure to me. Over several months, one of my add-ons was getting over 100 downloads a week without any promotion. But my ADU remains almost constant every week. It may increase by a few, but compared to the number of downloads, it only seemed like I got an abnormally low number of conversions. Less than 15% of users who downloaded my add-on turned into a ADU.

This didn’t seem right, so for 0.7 release of Safe extension, I added some code that sent me some info whenever someone uninstalled from the Add-ons Manager.

According to the add-ons dashboard, I had 78 ADU users for version 0.7 (submitted 2009-08-14. Averaged over a period of 1 week.).

How many downloads since it was uploaded? About 659 (I likely uploaded it late evening, so it might be less then that). So about 11% of the users that downloaded the extension didn’t uninstall it. But how many users chose to uninstall it using the Add-ons manager?

Ten.

So what of the other 500+ users? How did they uninstall my extension? I wondered whether web crawlers were downloading my extension. 500 seems like an awfully big number. Maybe a broken crawler? Well, actually, it turned out that AMO’s robot.txt did not exclude robots from downloading extensions at all. And how often a crawler visits is determined by the provider. Google cache takes a snapshot around once every week for me.

I realized that these numbers won’t be accurate because there are more ways to uninstall an add-on, including new profile or deleting the add-ons folder from the profile. But these seem like rare cases. Certainly not responsible for such a misleading number.

I filed and fixed a earlier bug to have robots.txt exclude crawlers from the /downloads/ path of each of our localized versions of AMO.

After 4 weeks, my stats have leveled off and the number of downloads have dropped by about 10 a day. My add-on downloads dropped from >10 to about 3 a day. This won’t be considerable to popular add-ons (AdBlock Plus shows no difference, they are still getting 80,000 downloads a day). Looking at the statistics on AMO, total downloads have dropped over 100,000 a day since the stuff went live last month. Good stuff.

As the addon review queue grows beyond 600 nominated and updated addons, it is more important than ever to make sure your extension passes review the first time around. Editors have a review guide, and a well hidden but publicly viewable set of policies. But here is a quick list of the most cited reasons for addon refusal :

1. Addon should have at least 3 user reviews before being nominated. External reviews count too, but you have to mention them in your nomination message. Softpedia reviews do not count.
2. Wrap your loose variables. All objects, variables, and anything that your addon makes global should be wrapped to avoid conflicts with other addons.
3. Look at the error console. Is your extension throwing up javascript errors? Fix it. There are some options you can set in about:config to help you with this.
4. You break functionality in the host application (Firefox, Thunderbird, etc.).
5. Your extension doesn’t work properly, or showing unexpected results. This is what user reviews are expected to catch, but you really should get someone who wasn’t involved to test and report bugs.

There are other less common things that can get you busted too. I’ll just list them here for completeness sake :

5. Including remote javascript/css or other files, anywhere. Include them in your xpi file instead.
6. CSS warnings on the error console if your submitting a theme.

If you have any doubts, check the public policies page linked above.

And don’t ask when your extension will be reviewed in the comments. Because every answer will be the same : When someone gets around to it. It could be sooner if you’d help!

I made a post several months ago about an diffing zippy files on the web. While that stuff landed, it was difficult to use because I deferred actually showing what files changed to a later date. oops

Well, that made it nearly useless, because it was less effort to download each xpi file and do a diff locally.

Well, I’m glad to say that I’ve right a worlds wrong. Some stuff I was working on finally landed recently (can’t remember when. But it wasn’t working two days ago. So somewhere between Monday and today). So you may notice a few changes.

The first being the side panel that shows all the files. Any files that were modified appear italicized. Which is a bit subtle, but is the only indication I could give that wouldn’t make it stick out like a bad rash, or a honda element. Suggestions welcome.

Side Panel

So this pretty much completes what was started. Only some minor improvements were made since the last post. Including a wikipedia colour style diff :

Full screen view

I hope that this will be useful to AMO editors and help speed up the reviews. Which is in much better shape than they were two months ago.

I’ve been sorta hiding this behind a mac that is currently behind a locked building in an office somewhere in Mountain View, but thought that now was a good time as any to demonstrate what I have been working on.

The project is called My Lists. In a nutshell, it allows users to generate and publish a list of addons. For example, you may want to generate a list of the best web developers extensions you can find. So you include extensions such as the Extension Developer’s extension, and Firebug. You can then share this list with friends, or post a link to your website. Other users can then directly download these extensions from that page.

You can get a demonstration of what a list looks like at a remora instance I put up on this site. Of course, you need a username/password to generate your own list (and find the page that lets you do it ).

The hope is that this list will be used with other websites, through a web service. I currently have a service that does that by reading XML from a post request.

None of this is really done. Everything is very dis-jointed. You can’t tell what lists a user created or who created a list. Still needs polish. But just wanted to get the project out there in the open.

As an AMO editor, one thing you have to do is code review for security flaws. When doing update reviews, the best way to do this is to download the extension update that is currently in sandbox, and the last public release and unzip the zippy and jar files (unless your lucky and your diff program does this for you), than compare the results using a tool such as kDiff3, meld, or WinMerge.

I’m trying to change that by starting a project that will let you compare two files online. I’ve done some work and think it’s a good time to get my idea out to those who will use it.

Here is a screenshot of the output. You can test a sample output at this page :

One of the first thing you might notice is that this isn’t a side-by-side diff. The reason for that is that editors typically aren’t worried about what was taken out, but what was put in (while what was taken out might be more useful for extension developers). There is also the code that hasn’t changed, which is useful for referencing functions if it is ever needed.

It’s a simple php file. I hope to have some feedback whether people will use this tool or not (and saying “I use x because I know it best” is totally fine too. I’m trying to focus my energy on what will be used).

I started writing this a week and a half ago, but just finished it today.

First day at interning at Mozilla. I finally found out what I get to do this summer. I got the OK to blog about it, because you know how secret them Mozilla folks are about their secret in-house project (ie. What is this guy up to? ).

The actual wiki page was apparently out in the open, but no-one heard about it. It’s called WildOnAddons. While a new name is, IMO, mandatory, it’s actually a pretty neat idea. There are many great extensions such as Ted’s Extension Developer’s Extension that aren’t hosted on AMO. Some other extensions are hosted on AMO, but frequently have updates much sooner on their website before it goes public.

Sometimes, extensions come in bundled with packages such as Norton and McAfeee. Google Notebook is one of many Google Labs extension hosted on their own server.

In short, they’re hosted everywhere. But that presents a problem, how many are out there and can find and index them?

This is actually a lot harder then going on google and typing filetype:xpi, because according to those results, AMO only has 78 extensions. In fact, there are several repositories of addons each catering to a different crowd (yes, we are counting all addons). While I don’t think that AMO can satisfy everyone all the time. It might help us figure out how many extensions are out there and how many are hosted on our servers. Actually figuring this out will take a lot of work, and not as straight-forward as it sounds (ie. All of AMO’s sandboxed addons require authentication, so a web crawler would have to know about it if we were crawling through the web), but it will be worth it in the end.

I’ll keep blogging about it under wildon tag RSS feed if your interested on how progress goes.

I’ve been writing an extension that uses part of Tinderbox’s (56K warning) json.js file. It’s an interesting experience, since I haven’t done much work with JSON before.

At over a meg, this json file takes quite a while to load. While parsing it and playing around with it for my own purposes, I noticed a few things that I would like to see :

• A JSON formatter refuses to touch json.js because it is too big. So I had to do one of my own (need to upload it once I pretty it up).
• JavaScript reportedly can load compressed javascript files. It would be mighty dandy for it to load compressed json (shrinking it down to a much smaller 84KB). Maybe it can! I have not been very successful
• Tinderboxe’s JSON output isn’t real JSON, but that has been noted and filed in bugzilla. Hmm, I wondered why an error message was being written to my console
• I haven’t yet found a (simple) way to associate a check-in with a time/person, so I can’t “blame” a burning build on anyone. It’s got to the point where I was just about to comment asking them to reopen the bug, but loading in a new json.js file I noted some things that were not in the previous file. Mainly, the last json.js file I downloaded all had ‘undef’ in one section, and this one has a few names and id so I can sorta match when they checked in.
• There are files littered in tinderbox to a bunch of this data that json.js is supposed to replace (See Tinderbox’s README file, Other Files section). When I just started using JSON, the almost CSV file was both direct to the point and pretty much what I wanted out of the JSON file anyways. But it was still missing some things, like who checked in, the log file, the stats. And another file sorta had that information. So it was spread out. I am really hoping that json.js consolidates and really fixes this problem. But at the same time, it is also fairly complex.

Anyways, it will be all fun and worth it when this is done. At least, I’ll be using it