Update (12:55 pm ET): Akamai appears to have fixed the problem, and services including Steam are either back online or headed that way. Akamai said it will continue to monitor the situation to ensure that nothing falls out of place, but for now Steam appears to be fully back to normal.
We have implemented a fix for this issue, and based on current observations, the service is resuming normal operations. We will continue to monitor to ensure that the impact has been fully mitigated.July 22, 2021
As you may have already noticed, Steam is down: The Unofficial Steam Status site indicates that most services, including the store and community, are currently unavailable.
The good news, such as it is, is that it's not just Steam. The outage is apparently the result of problems at Akamai's Edge DNS Services, which is currently suffering an "emerging issue" that's also impacting other services. GamesRadar has reported that the PlayStation Network is also down, for instance, and Epic is having trouble too, although right now it's slow but still seems to be accessible.
The Epic Games Store/Launcher is currently impacted by a broader internet issue affecting a range of online services. We'll provide an update when players are able to use the Store/Launcher as normal.July 22, 2021
There's no word about the problem from Valve at this point, but it's really out of Valve's hands: According to The Verge, other services including banks, brokerages, and possibly even some 911 services were also been impacted by the outage. Akamai said it's working on the issue and will post regular status updates.
We'll keep an eye on things and let you know when it's back.