Don't worry, Slack is actually really cool and familiar. It's not something only Agoraphobic Pterodactyl Geeks *cough*Andrew*cough* will understand. There's actually a lot more it can do already. As Atlassian grows, I believe there will be even more integration with their products. So stop being scared of change and get excited for Slack!
Here's what you as the creative professional can do as far as global customization and branding to get your company going... once you log on, and without admin assistance.
NOTE: Some of this may be unavailable due to administrators who are paranoid of trolls.
Branding for Corporate Identity
The absolute first thing you need to do once you've logged into the desktop client is go to Preferences > Sidebar. Then, scroll to the bottom and play with the colors in a custom theme. Once you have the colors how you want them, locate the text box at the bottom. Copy the contents and paste them into your #general room. This will give everyone an actual button to instantly change their theme.
NOTE: This adds a color swatch next to every HEX value, which you may be familiar with.
Though part of me wishes there were more color/theme options, another part of me is glad there isn't because that could get too complicated. The changes you make also reflect on the mobile app. My advice is to create a light theme and a dark theme if your brand color pallet allows for them. Here's ours if you want to try it out:
Isos Light theme
Isos Dark theme
Emojis and Loading Messages for Corporate Culture Customization
Next, you'll want to add some custom emojis. Log in to https://[yourslackcname].slack.com/customize/emoji and toss 'em in. Make sure your custom emojis are 128x128px square (and keep them SFW). As part of your custom emoji set, it is a good idea to add any logos, icons, or product icons pertaining to your company. Atlassian icons may be added as the partnership evolves, but you can add them in yourself for now. Add some funny ones. Add heads of your coworkers.
That's March. It's the first one we brought over from HipChat.
If you're on the Emoji tab, hit the Loading Messages tab. These can be really funny and give a little personality to your communications. They only show VERY briefly as long as your computer isn't slow. So, be sure to make them short and quirky... Like "Sometimes I ... garlic mashed potatoes" or "Today let's try to not make fun of the noobs... HAHAHA! Yeah, I'll make sure to do that!" or "Did Sean order another cold brew keg yet?" Also, keep it SFW. If your company is larger and you need to be a little more general, do something like one of those inspirational text memes from your wife's Facebook page, or just use the tips or canned messages that Slack provides. Do consider your whole audience when creating messages, and make sure they fit your company culture.
Apps and Integrations for Creativity
Slack, like Atlassian, has a ton of 3rd-party add-ons called "Apps." You can check them out here. As long as you're logged in through your browser, they're easy to install. I wouldn't go crazy installing Apps because you might anger the pterodactyls *cough*Andrew*cough* and they'll make it so you can't install anything on your own anymore. Visit the Slack App Directory for more. There are tons of apps for your pterodactyls and I'm sure they've already got the ones they want installed. Here are a few to get you started to boost creative productivity.
An "Eessential App" — This one works with sharing and managing your Google Drive. We use Google Drive as our Digital Asset Management area. This seems to work well, although I haven't tested it thoroughly. It does require some individual configuration, but I'm the main one sharing most digital assets... but it's super useful on the nth time that a person asks, "Hey Tad, can you shoot me our logo?"
This one works with a Chrome extension, allowing you to quickly take a screenshot and mark it up for people to look at. It is a subscription service, though [icon name="frown-o" class="" unprefixed_class=""].
I'll admit, I don't use InVision App yet, but I have been planning on it. It looks like the integration with Slack does some slick notifications that seem very useful for collaboration. There are also a slew of other design collaboration apps that work with slack, in case you use something other than InVision App already. If you have a preference, chances are they have a Slack app.
After installing this to your Wordpress site, you'll have to go to https://api.slack.com/ and create an app so that you can get a Webhook URL to set it up. It'll allow you to display a variety of notifications from your site to specified channels. We currently have it set up to notify a channel when blog posts are published.
Don't forget to delete HipChat, or else it'll haunt you.