DarkN: here's some info on hair porosity. The test is to put a couple of strands of hair in water and if they sink after 2-5 minutes you have porous hair. If they don't sink, you have low porosity. Not sure where normal comes in...sinks after 20 minutes?? If your hair is chemically treated or colored, or you use heat, your hair might be highly porous or fairly porous. To fill in the holes from these processes, you'd need to do protein treatments (PTs), always followed by a deep conditioning treatment (DT). The protein and porosity forums have more info...
Originally Posted by coricourt
From Live Curly Live Free

Since coarse hair carries an excessive protein structure, putting protein-based
products on hair that is already protein-heavy will increase the hair structure to the point the hair strand will become just like a broom straw: hard, difficult if not impossible to bend, and very dry. Products that are protein-based should be avoided in favor of those with plenty of emollients.

Live Curly Live Free - Curly Hair Basics
To determine your own hair's porosity, grasp a hair strand firmly between your fingers. Slide the thumb and index finger of your other hand from end to scalp (opposite direction as for texture test). If your fingers "catch" going up the strand, or feel like they are ruffling up the hair strand, your hair is overly porous. If it is smooth, you have normal porosity. If your fingers move very fast up the hair strand and it feels exceptionally slick, you have low porosity.