The description of the "Yearling" badge reads
Active member for a year, earning at least 200 reputation.
My question is, what does it mean being an active member? Is it visiting the site every day?
The phrase "Active member for a year" is irrelevant to the implementation of the badge, and just describes the general idea of what the badge is supposed to be rewarding. The other part about "earning at least 200 reputation" is misleading, because the rule is:
On the $n$th anniversary of your joining a given SE site, if your reputation is greater than or equal to $200n$, then you are awarded a Yearling badge on that site.
So if you earn $1000$ reputation in your first year, you could never visit the site again and still get the Yearling badge each anniversary of your joining the site, until the 6th anniversary.
Copy/pasted from meta.SO:
- silver; awarded multiple times
reputation ≥ (number of years as an active user) × 200
- The script that awards this badge only runs on the anniversary of you joining the site
- If you do not qualify for Yearling on an anniversary, but do meet it before your next anniversary, the badge will be awarded
- Example: A user who earns 190 rep in his first year will not be awarded Yearling on his first anniversary. If the user earns 40 more rep exactly one month after the first anniversary, the Yearling badge will be awarded the next time the badge script runs. This is because (190 + 40 = 230 rep) > (200 rep / year × 1 1/12th years = 217 rep)
- The badge used to require only
years × 100rep; this was changed after the account association bonus was implemented