Since 2019, Google treats rel=nofollow as a hint, not a strict directive. They may pass PageRank and ranking signals through nofollow links if they decide it is appropriate. They mostly do not, but they reserve the right.
Three related attributes exist: rel='nofollow' (general purpose), rel='sponsored' (for paid links), rel='ugc' (for user-generated content like comments). Use the most specific one that applies.
Roughly 60-80% follow links from editorially earned mentions, 15-30% nofollow from social, forums, and high-traffic referrers, 5-10% sponsored. A profile that is 100% follow looks unnatural and tends to attract algorithmic scrutiny.
No. They are a healthy part of a natural backlink profile and they drive real referral traffic. Pursue them when the audience is right.
Yes, indirectly — Wikipedia citations are read by LLMs as authority signals, even when the outbound link is nofollow.
Disclosure is required under FTC and similar Canadian rules; the technical attribute is required by Google's policy. Use both.
No — there is no penalty for receiving nofollow links. The penalty is for engaging in link schemes, regardless of attribute.