It starts with a line under a phrase.

Paul Graham, How to Get Startup Ideas.

Thirty of them on this piece.

Three kinds, colour-coded.

Grey with a question mark is Source: where a claim came from.

Purple with a plus is Expand: the wider context.

Blue with an i is Define, what a term means, and this piece happens to use the first two.

Select a span and the card opens against it.

Source, on 'It's exceptionally rare for startups to be killed by competitors'.

The badge names the kind and where the answer came from.

Expand, on 'schlep blindness'.

A phrase the essay coins and then uses.

The card carries the wider context, and sometimes a link straight into something already in your Library.

The glyph waits for your cursor, and takes up no width, so the page stays put as you read.

When a Source comes back empty, it shows you the claim and a button, Look this up, and leaves the finding to you.

Thirty marks on seven thousand words.

Few and careful, because one wrong annotation costs more than ten missing ones.

This piece carries marks and no Strata.

The two are judged separately, so a piece can have one and not the other.

Three kinds, and you can read straight past all of them if you want to.