BITCOIN vs ALTCOINS
The higher market dominance for BTC, the less funds are in altcoins. That fact alone means a lot.
To watch the overall direction of the market, you follow the market cap. To determine if Bitcoin is bullish or Alts are bullish, you look to Bitcoin dominance.
When Altcoins made the amazing run from Dec2017 to Jan15,2018, BTC reached an all time low of 33% dominance. When it was closing in on $20,000 USD, the dominance was 67%.
Right now, Bitcoin is back over 40%. And as the market rebounds/recovers, the buyers are looking to Bitcoin and ICOs. This is a cycle that has happened many times before.