I think we are in danger here of confusing etiquette in public face to face, with online etiquette which is by default a different thing. Yes, manners still apply but the simple fact that one can post and then walk away from the conversation, go to work, the pub, even go birding (!) means that any delay in responding can easily be misinterpreted. Yes David, a lack of response can be frustrating but people do have more important things to do than post on Birdforum. Added to this, and expectations from forum to forum and website to website vary greatly. With regards other hobbies, one forum I am a member of is very lively and supportive, pretty much all posts responded to quickly. Another is sparse in comparison and there is often a delay in responding, and because of this some posts get lost over time. I don't take this personally.
As I have said before, a number of people lurk on here and offer nothing, just taking information I expect. Again, nothing personal, let them get on with it. They are missing out because the forum can be a great place if we want it to be.
There are only so many shits to give in life; I would suggest this is not one of them.
Cheers,
Jim.