Followers
The permanent count on your channel, ordered against the channel link. One of the two figures Affiliate measures.
3 services available
Services for Twitch
Twitch has a published threshold for its Affiliate programme, and two of the three services below are the figures it counts. Each has its own page with the current packages, rate and delivery window.
Before you choose
Twitch has a stated requirement rather than a vague one. Affiliate asks for 50 followers and an average of 3 concurrent viewers across streams of a certain length in a 30-day window. That makes followers and live viewers the two services with a concrete use here, and it also explains why they behave so differently.
Followers are permanent. They sit on your channel whether you are live or not, they are ordered against your channel link, and they accumulate. Live viewers are the opposite: they exist only while you are actually broadcasting, they are ordered once you are on air, and they leave when the stream ends. There is nothing to place against a stream that has not begun.
Channel views are the third and the least useful of the three for the threshold, because Twitch does not count them toward Affiliate. They read as history rather than as activity.
The practical order matters. Live viewers bought while you stream to an empty channel raise the average that Affiliate measures, but the average is measured across your streams, not within one. Placing the order on a single long stream and none on the others moves the number less than spreading it does.