How Does Market Making Work? (discretionary)

[Wide Tailz]

Quote from thesniper:

I think 90% of profitable daytraders are just market makers.

And the 10%?

How very interesting how The Guru from the thread "why is the obvious, not so obvious" claimed that 90% of the time you BLSH / SHBL, 10% of the time you BHSH / SLBL.

Could these 10%'ers be intraday trend followers?