What are /r/gnuplot's favorite Products & Services?

From 3.5 billion Reddit comments

If you are researching plotting engines I think the "change of mind" came with "Grammar of graphics" A book that analysed how graphics were made and what was their "language".

If you need to know how these plotting engines born, Gnuplot has some nice info in it's webpage (Just about how gnuplot born, but it's one of the first).

Then it all depends on what exactly do you want to know about plotting engines.