(1) Switching a bit from 0 to 1 or 1 to 0.

(2) Same as bit manipulation which is processing individual bits within a byte. This is considered to be very low-level programming and is often used in graphics and systems programming.

(3) Similar to computer geek, bit flipper is the slang term used to describe an individual with a passion for computers and electronic devices to the exclusion of other normal human interests.  Usually has a large cache of electronic toys or gadgets. Depending on the context, it can be used in either a derogatory or affectionate manner. Synonymous with geek or nerd.

Data Representation
This is Chapter 1 of Randall Hyde's book, "Art of Assembly Language." It describes the binary and hexadecimal numbering systems, binary data organization (bits, nibbles, bytes, words, and double words), signed and unsigned numbering systems, arithmetic, logical, shift, and rotate operations on binary values, bit fields and packed data, and the ASCII character set.