Capacity (BTC)
Node count
Channel count
The Lightning Network is a second layer (layer 2) on top of Bitcoin for instant payments with minimal fees. Capacity is the total amount of BTC locked in payment channels.
The numbers read in pairs, not one by one. Capacity in BTC moves differently from capacity in dollars: a price drop can cut the dollar figure by a third without a single satoshi leaving the network — so the BTC number tells you about the network and the dollar number tells you about the market. The same goes for node and channel counts: fewer nodes with rising capacity means consolidation into larger, better-connected nodes, not fading interest.
Capacity as a share of total bitcoin supply is still a fraction of a percent, and that is how it should be read — Lightning is not a measure of Bitcoin adoption, it is a measure of payment traffic on the second layer. And because public statistics only see public channels, real capacity is higher than any chart shows, this one included.