The context: A person [the "I" in the sentence ] wanted to read another's posters comments/analysis of the debate and referenced a certain posting number.
This thought, "looking forward to ...", was formed [by 'I'] before the posting was made.
I'd been looking forward to your analysis of the debate. Sad that you weren't on form.
"I" could also have written it using the past continuous/progressive;
I was looking
forward to your analysis of the debate.
To my mind the use of the past perfect progressive/continuous shows a greater degree of importance, or a greater degree of formality, or, possibly, in this case, the use of this form as a form of feigned importance, a sarcastic response.