書き込みによると means "according to the entry/note."
書き込み = a (handwritten) note; jotting; an entry.
によると = a JLPT 1 grammar point that means "according to". You can read more on this grammatical form here.
Hope this helps!
I'm reading a JLPT N5 graded text (to practice reading with kanjis) and I understand all of it except for the following sentence:
ペットとしてしいくするのはかんたんです。
I don't understand the として in that sentence. I looked it up on http://jgram.org and it's listed as an N2 level expression, so I guess it's q...