He didn't mention two that annoy me:
1. The "What show should I see?" threads. Someone usually says I'm going to see X, Y and Z and for the fourth slot I can't decide between Once or Nice Work. Which should I see? Some will answer the question, while many others will say neither- go see ____ instead. Pretty soon they'll have 10 answers for Once, 10 for Nice Work and 20 for 20 other shows. There is usually a thread for every show on Broadway, and most of the major productions Off-Broadway filled with plenty of reviews and comments. No need for people to ask strangers who have no idea what their tastes are what they should go see.
2. The threads about helping someone pick a song for a certain occasion, and I fully admit I'm guilty of sometimes answering these threads. Some of them are so ridiculous and specific in their scenarios it would be near impossible to find a song that fits. "I need a duet between a bass and tenor for my niece's 3rd grade graduation that is mostly comic, but has a hint of melancholy about growing up too fast." The answers are usually equally as stupid- either too esoteric, songs that don't have readily available sheet music, or just plain bad suggestions that don't fit the topic.
Marie: Don't be in such a hurry about that pretty little chippy in Frisco.
Tony: Eh, she's a no chip!