Repeatable Read vs Snapshot Isolation

I liked this article because it demonstrates the anomalies.

(For some reason the <title> tag on the page itself is totally wrong and just contains the post's slug. The actual title is in the <h1> at the top.)

PostgreSQL uses snapshot isolation internally, even in its default isolation level of Read Committed.

Kinda, both Postgres and MSSQL use "Read Committed Snapshot Isolation" by default, which is basically per-statement (rather than per-transaction) SI.