PowerShell providers are drivers for PowerShell to navigate things besides the file system. For their part, modules are, at this point, far and away the most common type of PowerShell extensibility feature you will see.
There are authentication systems -- DomainKeys and its successor DKIM -- that try to mitigate some of the risk of trusting that emails are actually from who they say they are from.
Large shops will find many reasons for making the switch. Businesses of other sizes might have to do a pretty thorough cost-benefit analysis given the new pricing structure.
Here's how to create both local and cloud-based backups with this 'surprisingly good' software, and why it’s a good idea, at least for Microsoft-heavy shops.
Finally, a way around the problem of administrator passwords that are identical across machines, just waiting to be scooped up in pass-the-hash-attacks.