How to activate the Site Feed feature for every Site in a Site Collection in SharePoint 2013

Important: This Script must run as Farm Administrator, because you need Administrator Permissions on every MySite which you probably won't have as a regular admin. When you get this error:

Enable-SPFeature : SiteFeedFeatureReceiver: can only be enabled on the same farm where MySites are deployed.

...then this might be the case.

So just open SharePoint Management Shell as Farm/Site Collection Administrator via "Run As" and use this script:

$feat = "SiteFeed"
$site = Get-SPSite http://webapp/UrlToYourSiteCollection
$site | Get-SPWeb -limit all | ForEach-Object {Enable-SPFeature -Identity $feat -Url $_.Url}

That's it. Now the Site Feed Feature should be activated in all Sites unter your site collection.