In the past two weeks, it seems the big stories in architecture have been focused around the world's biggest cities, with developments in London, Chicago and San Francisco grabbing headlines.

Continuing our series of round-ups of ArchDaily readers' responses to such attention-grabbing stories, recent articles sparked interesting arguments about MAD's newly-approved Lucas Museum, Snøhetta's almost-complete extension to SFMOMA, and Renzo Piano's recently-revealed "Skinny Shard" in London, as well as discussions over the power of developers to shape architecture in New York. Read on to find out what readers had to say.