[lockhouse]

Also for a company the size of Microsoft, 30 million accounts seems very small. What user accounts would this database even contain?

This whole thing seems a bit fishy.

[sdflhasjd]

MITM'd login services perhaps? It does seem like a small number for Microsoft. Like robbing a bank and making off with $50

[doctaj]

Could be an event like Microsoft Build conference or something.

[wlesieutre]

Or the 100 "sample" accounts are sourced from unrelated phishing and there is no breach. Most of the phishing emails I get lately are trying to get me to fill out a fake MS login page.