In the early days, though it's still true now, one of Firefox's biggest pluses was support for add-ons, modules that could be installed to expand the functionality of the browser way beyond what Mozilla envisioned.
Add-ons/extensions are still a big part of the Firefox experience today, but they're also a part of the experience on any browser, Chrome in particular.
What's more, because it started out so early, Mozilla is finding it hard to convince developers to adopt more "modern" add-on techniques, like "restartless" extensions or what Mozilla calls bootstrapped extensions.
These offer users the great advantage of not having to restart the browser to install them, meaning they're much more likely to experiment with new add-ons.
But restartless extensions offer quite a lot of advantages to developers as well, besides having their extensions installed by more people.
Wladimir Palant, creator of Adblock Plus, has an interesting explanation on why he switched all of his addons to the restartless model and what were some of the challenges.
"An extension that will install without requiring a Firefox restart? This was a nightmare to develop not too long ago. Fortunately, things changed and the last showstopper bug was fixed in Firefox 8," he explained
"Effort to create a restartless extension is acceptable now. In fact, I have converted all my extensions and removed support for classic non-restartless extensions from my build tools — I am certain that I am not going back," he said.
"For me, the advantages clearly outweigh the disadvantages. If you already have a classic extension then you may wait with converting it until you actually have time for that. But if you are planning a new extension then you certainly should make it restartless," he added.
There are some disadvantages to using such extensions, but he believes the payoff is worth it. Hopefully, more Firefox add-on developers will start heeding the advice and start making all of their extensions restartless.