With Mefi, one could always quote someone in reply to make things clear. Some of the best discussions online happen over at Metafilter. (I find HN interesting due to it's SV audience, but it functionally feels like an old version of reddit.)
What hurts both G+ (and HN) is the absence of a specific blockquote markdown.
None of italicize everything quoted, "put quotes in quotes (especially for long passages)", nor > prefix quotes with a greater-than sign work particularly well IMO. Though I suppose they generally suffice.
Blockquotes have been supported in markdown as the ">" prefix since the very beginning. It's a mystery that HN doesn't support it when even reddit does.
