It seems people believe it’s more a stand-off with Twitter than Facebook.
Google+ Tops Ten Million, Makes Lots of Money – HotHardware
Google+ Has Made Twitter Boring — Here’s What Twitter Should Do About It
Twitter has never been anything to phone home about from a UI/UX point-of-view, but it’s very good at aggregating information in a condensed no-nonsense way. That’s its power.
Regarding “2. Pictures and videos.”: You know who to ask.
Regarding “4. No API, no auto pushing of content.”: I’d be very surprised if Google+ will not have an API for publishing content. That’s what made Twitter a success. Remember that the PC/mobile apps and services all use this API, and Twitizer does too.
Commentary on the above: Asking Twitter To Commit Suicide With A Google+ Dagger – TechCrunch