It's been called "Silicon Valley's Hottest Startup," grabbed a TechCrunch Crunchie award for "Fastest Rising Startup," and garnered attention when it formed an $80 million venture fund to invest in other startups. Slack is hot--there's no doubt about it. But if you're one of the 2.3 million people using the messaging platform daily, the questions is--are you using it to the best of your ability? For example, have you thought about opening up your account to clients and vendors? Rebecca Reeve, founder and principal of tech PR firm Rsquared Communication has done it with clients including Slack, Trello, Digit, Eventbase and Zendrive. In fact, her firm was the first agency to beta test Slack prior to public launch. Here's how she says you can use Slack with your outside partners, as well.

1. Set up restricted accounts.

If you're paying to use Slack you have the ability to add external parties to a team. In contrast to the full access to public channels that new employees see when they're added, setting up a restricted user means you can invite external parties into a team and give access to only the channels appropriate to their project. "We use Slack with all of our clients," she says. "We've found that the most effective way of getting started is to create two channels: one for day-to-day tactical conversations with our main point-of-contact, and a second channel for sharing updates with the executive team and key stakeholders."

2. Manage your expectations.

Using Slack externally is a bit different than using it internally. For one thing, employees are focused on just your business, but outside parties have their own clients, vendors and responsibilities they're involved with. In other words, while you may expect someone within your company to respond to a message immediately, an external partner may be working on something else at the moment so it's important to establish your expectations about response times up front.

3. Use Slack to map out key players on a project.

A big part of any onboarding experience is getting everyone connected, something Slack does well by immediately making an external party a visible member of the team. Slack's user bio info--such as profile photos, job titles, and reporting structure--helps your team identify who's who on a project. "Once in the team, restricted users can easily get in touch with anyone in the company without waiting in a bottleneck for introductions," she says. "This visibility is especially important if the vendor is working remotely."

4. Manage noise.

Features like muting, direct messaging, and setting alerts to ping only when someone directly mentions you will keep you in the loop without getting bombarded by notifications.

5. Hold cross-functional team conversations.

As projects progress or teams grow, the need may arise for additional channels to manage new projects. It might mean pulling together a cross-functional team for a quick chat via private group direct message, or a more permanent group which gathers long-term in a private channel.

6. Use emojis to reduce noise and add some fun.

Like it or not, people use these silly little pictures all the time, including at work. In fact, punctuating your conversations with an emoji can infuse personality, humor, and warmth--especially across remote spaces--which is a critical component in team bonding. Reeve's team particularly likes emojis including "boom" to celebrate wins, "eyes" to indicate someone is reviewing something, "OK-hand" for approvals and "sparkles" to say "well done." In essence, using emojis this way reduces the need to light up a channel with "Great job!" or "OK." The sentiment still comes through, but without the mental load of processing another message. "My personal favorite is 'point up' to give a heavy endorsement of what's been said in the message above," she says.

7. Let people know you're gone with OOO headers.

Another great hack, especially for large teams in which vacation or travel schedules aren't widely known, is updating a user name with vacation or travel emojis. For example, if you're traveling to Paris you could use French flag and Eiffel tower emojis after your name, punctuated by "until" whatever date you will be back in the office. Another idea: Name, OOO until X-date, followed by a baby and bottle emoji, to indicate paternity leave.

"By removing many of the barriers and dead-ends of email,  Slack allows outsiders to more autonomously find and connect with the resources they need without bogging a project down," she says. "If you let them do it you'll be rewarded with better performance and innovation on whatever they're working on."