Recently, someone asked me what DOM is and why I should care.

It turns out that understanding Bitcoin dominance is key if you really want to know what's happening in the market.
It's not just a number; it's like the pulse of the entire ecosystem.

Basically, Bitcoin dominance (or btc.d) measures what percentage of the total crypto market capitalization Bitcoin represents.
Imagine the market as a pizza: if Bitcoin is 55% of the pizza, that means Bitcoin dominance is at 55%.
A few years ago, this was much higher, around 60-70%, but now it fluctuates around 50-55%.
The formula is simple: Bitcoin market cap divided by the total crypto market cap.

Why does this matter? Because Bitcoin is the gateway.
If you want to enter the crypto market, you almost always need BTC or USDT first.
And when altcoins crash, people return to Bitcoin to protect their capital.
It's like the safe haven of the market.

Now, there are four main scenarios you should know.
The first is the ideal one: Bitcoin rises and everything rises with it.
The market breathes confidence, fresh money comes in, everyone wins.
The second is when Bitcoin rises but altcoins fall, meaning capital is moving only into BTC, leaving the alts behind.
The third is the painful one: Bitcoin falls and drags everything down with it, because when the king is sick, the whole court trembles.
And the fourth is interesting: Bitcoin moves sideways or down, but altcoins rise or stay stable.
That's when Bitcoin is accumulating strength and altcoins are preparing for their own rally.

Look, the historical milestones of Bitcoin dominance are fascinating.
In 2016, Bitcoin was below $100 and accounted for over 90% of the market because there was practically nothing else.
In 2017, something crazy happened: ICOs exploded and Bitcoin dominance fell to 35%, the lowest ever seen.
Ethereum reached about 30% because everyone wanted ETH to participate in those projects.
By the end of 2017, BTC recovered to over 65% when it hit $20k.

But in January 2018, we saw the most brutal drop: Bitcoin dominance fell to 33% because big players took profits and moved into altcoins, then closed everything.
It was devastating.
Between 2018 and early 2019, things stabilized around 50-55%, where they were when this analysis was written.
Then in 2020, something important happened: when BTC collapsed to $3,800 in March, it then recovered strongly to $41k by the end of the year, and Bitcoin dominance nearly reached 74%.

So, what do you do when Bitcoin dominance rises?
If BTC rises and dominance also increases, it means Bitcoin is gaining ground, confidence is growing, and many sell altcoins to move into BTC.
It's hard for altcoins to rise in this scenario, but there are projects with solid fundamentals that can surprise you.
If dominance rises but BTC falls, that's dangerous: altcoins will fall even harder.

The important thing is not to look at Bitcoin dominance alone.
You need to combine this with other indices like TOTAL, TOTAL2, DEFI, and USDT.D to truly understand the flow of money.
That's why many beginners get lost—they don't see the full picture.
Understanding how Bitcoin dominance moves gives you a map to navigate this volatile market.