Mozilla Firefox is due for some big changes soon. By the end of 2015, Firefox will move to a more Chrome-like multi-process design. And, in a year to a year and a half, Firefox will abandon its current add-on system for one largely compatible with Chrome extensions.

These aren’t necessarily bad changes — in fact, they’re arguably big improvements. But Firefox seems to be abandoning its big advantage and becoming even more Chrome-like. The list of reasons to use Firefox over Chrome is shrinking.

A Multi-Process, Sandboxed Firefox is Almost Here

Firefox currently stands alone as the only single-process web browser. Chrome was multi-process when it launched, and other browsers like Internet Explorer, Microsoft Edge, Apple Safari, and Opera are all multi-process browsers now.

Actually, Firefox isn’t really single process anymore — it has a special plugin-container process it uses to isolate the Flash plug-in and other browser plug-ins from the rest of the browser. But, if you have an eight-core CPU and load eight web pages, they won’t run on eight cores — they’ll just run on a single one.

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Mozilla has had an on-again, off-again project to fix this named Electrolysis. The project was halted in 2011 because it was too hard, but it was restarted years later. Thankfully, it’s almost here. Multi-process Firefox is on by default in the current nightly builds of Firefox and will be rolled out to everyone in mid-December 2015, according to Mozilla. This means Firefox will finally perform better on multi-core CPUs when rendering multiple web pages.

As another bonus, security sandboxing will arrive along with Electrolysis. This is another long-awaited feature other browsers — yes, including Internet Explorer — have had for years. Firefox is currently the only web browser not making use of sandboxing technologies to limit the damage browser exploits can do. This has had real impacts in the real world — witness the recent malvertising attack that used a zero-day in Firefox to compromise Windows, Mac, and Linux users on a Russian website. Sandboxing likely would have prevented this, or at least would have required the attackers exploit a separate flaw in the sandbox as well.

WebExtensions Will Replace Firefox’s Powerful Extension Framework

Mozilla recently announced its intention to kill the current Firefox extension framework and replace it with something new. The new framework, named WebExtensions, is “largely compatible with the model used by Chrome and Opera.” Microsoft Edge is about to gain an extension framework that will also be largely compatible with Chrome’s extension framework — everyone but Apple seems to be jumping on this bandwagon and incorporating Chrome-like extensions.

Current XUL and XPCOM extensions will be deprecated and removed entirely within a year and a half. Those powerful add-ons you’re using in Firefox today? They’ll be gone at some point in the near future, replaced with add-ons much more like Chrome’s.

Now, this isn’t the end of the world. Mozilla wants to extend the Chrome extensions framework to add features to make extensions like NoScript possible and add sidebar support like the sidebar support in Opera. Mozilla wants to ensure current popular extensions can continue to work in the FIrefox of the future, and is working on making that happen.

And, what’s more, this is good news. Firefox’s powerful extension framework has led to a lot of teething problems, particularly when Mozilla jumped on board a Chrome-like rapid release cycle. It’s about to cause a lot more problems, as many extensions will need to be updated to support multi-process Firefox or they won’t work properly. Future projects like Servo — a new layout engine to perhaps one day replace Gecko — wouldn’t be compatible with the old extension system, either. And there should be an improvement in security, as extensions can be sandboxed a bit more and don’t all have access to everything.

But this rightly rubs some people the wrong way. Firefox’s extension system is about to become less powerful. Currently, browser extensions can do practically anything in Firefox. That leads to security problems, compatibility issues, and breakages during development. But it’s also Firefox’s big advantage — Firefox is the browser with the most powerful add-on framework, bar none. That’s about to no longer be true. Mozilla will add features to allow the most popular add-ons to continue to function, but less-used add-ons and future add-ons will be much more restricted in what they can do.

If Firefox no longer has the most powerful add-on framework, its biggest advantage over its competitors will be gone.

Firefox Has Been Following in Chrome’s Footsteps for Years

Of course, Firefox has been following in Chrome’s footsteps for a long time now. Shortly after Chrome launched, Mozilla jumped on-board a rapid release cycle that sees regular releases of Firefox every six weeks. This caused a lot of problems with broken add-ons because Firefox’s add-on framework was never designed for this.

Last year, Firefox received a new theme named Australis designed to be more “modern.” Many users considered this much more Chrome-like and balked at it. Firefox has also dumped the status bar, as Chrome did.

Other features have become increasingly Chrome-like, too. Firefox Sync was redesigned to use just a username and password instead of the old security key system — just like Chrome. You can now have both normal browsing and private browsing windows at once, like in Chrome. Mozilla has started packing in questionable features like Firefox Hello and Pocket integration, just as Google has built its own features into Chrome. Firefox can now play H.264 videos on the web, as other browsers can.

Mozilla is also only going to allow Mozilla-signed add-ons on the stable version of Firefox, requiring users switch to a developer version to install ones Mozilla hasn’t approved. Chrome is also limiting these for security reasons.

And Mozilla is about to come out with Firefox for iOS — a browser for iPhone and iPad that provides a different skin around Apple’s Safari renderer but allows you to sync with your Firefox account. Chrome for iOS works similarly, but Mozilla avoided doing this for years because they couldn’t use their own Gecko rendering engine.

Firefox Needs a Distinct Identity

Now, don’t get us wrong: Most of these changes are good. Even the most controversial ones like getting rid of the extension framework will probably be an improvement in the long run.

But there’s no doubt that Firefox is gradually losing its distinct identity. Abandoning the most powerful extension framework for an add-on model largely compatible with Chrome’s will be a huge blow to a vocal part of Firefox’s user base.

Mozilla has to answer an important question: Why use Firefox over Chrome? Mozilla would probably argue that Firefox is unique because it’s made by a non-profit company dedicated to making the web better, rather than big for-profit corporations that do more things like its competitors. It also uses Gecko, a different rendering engine, which hopefully helps preserve web standards through a variety of implementations. But is that really enough?

Firefox is now using Yahoo as its default search engine, and that certainly isn’t a big advantage. Go ahead — search “vlc” on Google, Bing, and Yahoo right now. Google will show you a big VLC download link without any misleading ads, Bing will show you some dangerously misleading ads but still point you toward the VLC download page, and Yahoo will show you a bunch of ads trying to get you to download malware without a clear indication of where you can get VLC. Firefox has the worst default search engine of any mainstream browser, and Mozilla certainly isn’t helping users by going with Yahoo.