A threat actor is offering a service in which they let customers search for keywords across over a thousand hacked mailboxes which likely belong to corporations.
I suspect this sort of service will gain traction in coming years as hacked corporate mail access is relatively common yet not often easily monetizable.
This would allow threat actors to harvest as many webmails as they can via info-stealers infections & bruteforcing and let sophisticated groups attempt to find secrets/credentials that would allow them to perform ransomware attacks, data breaches, etc.
Second image is from www.hudsonrock.com showing the incredible amount of office365 credentials that are in the hands of hackers because of employees downloading info-stealers