It’s official. Microsoft’s Edge browser is running on the Blink rendering engine and it’s available now.

Just over a year ago, I wrote about my feelings on this decision:

I’m sure the decision makes sound business sense for Microsoft, but it’s not good for the health of the web.

The importance of browser engine diversity is beautifully illustrated (literally) in Rachel’s The Ecological Impact of Browser Diversity.

But I was chatting to Amber the other day, and I mentioned how I can see the theoretical justification for Microsoft’s decision …even if I don’t quite buy it myself.

Picture, if you will, something I’ll call the bar of unity. It’s a measurement of how much collaboration is happening between browser makers.

In the early days of the web, the bar of unity was very low indeed. The two main browser vendors—Microsoft and Netscape—not only weren’t collaborating, they were actively splintering the languages of the web. One of them would invent a new HTML element, and the other would invent a completely different element to do the same thing (remember abbr and acronym). One of them would come up with one model for interacting with a document through JavaScript, and the other would come up with a completely different model to the same thing (remember document.all and document.layers).

There wasn’t enough collaboration. Our collective anger at this situation led directly to the creation of The Web Standards Project.

Eventually, those companies did start collaborating on standards at the W3C. The bar of unity was raised.

This has been the situation for most of the web’s history. Different browser makers agreed on standards, but went their own separate ways on implementation. That’s where they drew the line.

Now that line is being redrawn. The bar of unity is being raised. Now, a number of separate browser makers—Google, Samsung, Microsoft—not only collaborate on standards but also on implementation, sharing a codebase.

The bar of unity isn’t right at the top. Browsers can still differentiate in their user interfaces. Edge, for example, can—and does—offer very sensible defaults for blocking trackers. That’s much harder for Chrome to do, given that Google are amongst the worst offenders.

So these browsers are still competing, but the competition is no longer happening at the level of the rendering engine.

I can see how this looks like a positive development. In fact, from this point of view, Mozilla are getting in the way of progress by having a separate codebase (yes, this is a genuinely-held opinion by some people).

On the face of it, more unity sounds good. It sounds like more collaboration. More cooperation.

But then I think of situations where complete unity isn’t necessarily a good thing. Take political systems, for example. If you have hundreds of different political parties, that’s not ideal. But if you only have one political party, that’s very bad indeed!

There’s a sweet spot somewhere in between where there’s a base of level of agreement and cooperation, but there’s also plenty of room for disagreement and opposition. Right now, the browser landscape is just about still in that sweet spot. It’s like a two-party system where one party has a crushing majority. Checks and balances exist, but they’re in peril.

Firefox is one of the last remaining representatives offering an alternative. The least we can do is support it.