1. Why do some videos go viral while others seemingly underperform? HBR looks at how psychological response and social motivation drive video sharing. Apparently it doesn’t hurt to reach the “supersharers,” who are responsible for 82.4% of total video shares.
2. Slack’s integrations — from GitHub to Giphy — make the team collaboration app delightfully sticky. This week Slack announced a new feature providing apps with the native capability to “Add to Slack.” This feature debuts in 13 apps (including my daily favorite, Nuzzel) with more soon to follow.
3. As voice communications continue to spiral — does anyone remember the concept of “rollover minutes”? listen to voicemail anymore? — messaging apps proliferate. However, there are regional differences in adoption. Quartz reviews why WhatsApp lagged in U.S. markets compared to Snapchat and Kik, and what these apps will need to do to fend off Facebook Messenger.
4. The shooting of a news team in Virginia this week, and the rapid dissemination of footage online, led to some somber consideration of the implications of technology. These include the autoplay video behavior on Facebook and Twitter that can cause involuntary viewing, and the phenomenon of a senseless murder planned expressly with social media in mind.
5. Good manners are about making other people feel comfortable, and what feels comfortable has a way of changing over time. Pew breaks down for us all what mobile phone etiquette looks like in 2015. Related (in case you missed it): an excellent primer on how to be polite.

Weekend fun: Ever wanted to just pull up stakes and go? This clever art project has married census data to a “Why I am leaving X” letter format to make your parting thoughts painless. Or stay put; Harvard research says you can manage your stress by getting a dog.

Every Friday, find five, highly subjective pointers to compelling technologies, emerging trends, and interesting ideas that affect how we live and work digitally. Try out the Friday 5 archive, or sign up for a weekly email.