The tiers are rough follower bands: nano under 10k, micro 10k to 100k, macro 100k to 1m, and mega or celebrity above 1m. The pattern that matters is simple: as size goes up, reach grows but engagement and trust usually drop. Nano and micro punch above their weight on engagement and cost, which is why most brands now build campaigns around them. Use the bigger tiers for broad awareness and the smaller ones for trust and conversions.
The tiers are follower bands
Nano, micro, macro, mega. Rough ranges, not rules, but useful shorthand.
Engagement falls as size rises
Bigger reach, lower engagement and trust. That trade-off is the whole point.
Nano and micro overperform
Higher engagement, lower cost, more trust. The reason brands shifted down-tier.
Match tier to goal
Mega for awareness, micro and nano for engagement and conversions.