At its most basic level, as to derive means to get something from something other. Derive has two different primary ideas:

1. To extract or obtain something from something else: “I derive pleasure from riding my bike”

2. To create something based on or out of something else: “The 4790 CPU is derived from the 4770 CPU. Meaning

#2 is where we get words like “derivative,” meaning “something that was derived from something else”. In English, “creative” is a term often negative.

According to your explanations for this paragraph, I think some of this confusion comes from your grouping. The sentence is not this: “…able to (derive) real and demonstrable value from social networking…” Instead, it is logically grouped like this: “…able to (derive) (real and demonstrable value) from social networking…”

“Real” means modifying “demonstrable value,” that is, the value being derived is both real and demonstrable.