After being in beta since November, Microsoft Teams is now available to anyone with a suitable Office 365 subscription.

Teams is a group messaging application organized around chatrooms. Slack has become the darling of media and software development types, with its modern, Web-based take on what is actually an old-fashioned mode of computerized communication. Slack is text-heavy and line-oriented, much like the IRC that it mimics. Slack arguably brought IRC into the 21st century and added such niceties as persistent message storage so that you can see what happened before you even joined a particular channel. Slack also includes inline images and emoji. If instant messaging apps like Skype are an alternative to the telephone, Slack represents an alternative to standing around the office watercooler or hanging out in the break room.

Teams builds on this same heritage, but it adds a Microsoft twist: Rather than being a standalone service, as Slack is, Teams is an integrated part of Office 365.

This means that, for example, there's no additional account sign up or onboarding process. You just sign in with your existing O365 credentials. Similarly, Teams knows who's in your organization, and it understands all your existing groups.

Similarly, Teams is integrated with Skype for Business. Turning a text chat into something more face to face is just a button away, and Teams works within your browser. This is made more useful because Teams doesn't just support Slack and IRC-like persistent channels and one-to-one private messaging; Teams also allows the creation of small private groups. Unlike a channel, these aren't discoverable public places; they're more like a private e-mail chain or group direct message on Twitter.

Teams' communications flexibility is matched with a wide set of apps. Those include iOS, Android, and Windows mobile apps, a desktop Windows and macOS app (which is little more than a wrapper around the website, again as Slack does), and the web front-end itself.

As with Slack, there are various integrations with third-party services, there's a framework for building bots that you can chat to, and you can embed images and videos within the chat. Some of these integrations will be very familiar. Giphy's gif search is probably familiar to many Slack organizations, and it's present in Teams, too—though Microsoft does have some nice value-adds. For example, a meme/macro-builder lets you pick an image and then overlay text on it. Teams' handling of shared files seems a bit cleaner than Slack's, too. Again, it leverages that Office 365 integration: behind the scenes, it uses SharePoint.

Here's another twist on the Slack model (which Slack has in fact copied, surely in response to Microsoft's entrance into this market): Teams is oriented toward threaded messaging. Replies can be nested and collapsed beneath your messages. At Ars, we've experimented with Slack's threading. We're not fans. We generally use Slack for casual and freeform discussion. For that, the IRC line-by-line free-for-all is a solid model. The threading might make more sense if our usage were more structured, perhaps; the top level messages might be, say, story proposals, each with a thread of discussion and ideation attached below.

This focus on threading is unfortunate, and it arguably causes what is, for me, Teams' biggest failing. Its appearance is heavyweight; each top-level message takes up a lot of room, and you can't get too many of them on-screen at once. Threaded replies are, in fact, denser and more appealing. While there is some basic theming, Teams has no way to create a denser, more chatroom-style appearance, which is a shame. Threading may work for some organizations, but we want something more chat-like.

For a version 1 product, Teams is remarkable. Microsoft built it in about 21 months, and it's already well-rounded and polished. This is far richer than a minimal-viable product.

The final big way that Microsoft is distancing itself from Slack, and leveraging that Office 365 integration, is with the pricing. Teams has no free tier and no standalone pricing. Rather, Teams comes with Office 365 Business Essentials, Business Premium, Enterprise E1, E3, and E5 plans. There's no added cost—the per seat, per month price is the same today as it was yesterday. With the service now on by default, Office 365 customers can easily give Teams a spin.

For Office 365-using organizations that are interested in the Slack model of communication, Teams is already compelling. Google, too, is pushing Hangouts in a Slack-like direction, and I daresay that both products will become the "Slack of choice" for Office 365 and G-Suite-using organizations, respectively. If Teams could better mimic the wall of text that I grew to love in BitchX all those years ago, it would be better still.

Given the positioning and the integration, Microsoft's bundling and refusal to offer a standalone version makes sense. But it means that Microsoft isn't going to be able to take advantage of Slack's heroin-like business model, in which the free tier gets you hooked in the hope that you end up paying money for some improved functionality. This may also make Slack harder to use for ad hoc or cross-organization collaboration. I've seen Slack channels used for, for example, collaboration around open-source projects. While this is unlikely to make a cent for Slack, it certainly gets people familiar with and keen on the product. In this space, Teams will inevitably miss out. But with the dearth of paying customers, Microsoft might not be too upset.