[rgallagher27]

Things like mobile/webisite analytics events. User A clicked this menu item, User B viewed this images etc All streamed into S3 in chunks of smallish files.

It's cheaper to store them in S3 over a DB and use tools like Athena or Redshift spectrum to query.

[wackget]

Wow. What makes it cheaper than using a DB? Is it just because the DB will create some additional metadata about each stored row or something?

[bpicolo]

S3 is often essentially a database in these scenarios. You store columnar data format files in S3, and various analytical systems can query with S3 as a massive backing storage.