Am I alone in thinking that it would be confusing and unnecessary to have a "save for later" feature in the form of "favourite" as well as "save for later" in the form of "bookmark" side by side? 
@Gargron
I'd suggest putting the bookmark/save for later option in the [...]-menu, and not just next to the star.
It is presumably less often you want to (perhaps temporarily) save a toot to:
- read a long thread / big linked document
- respond properly later
- follow a debate you're undecided about
- look at when you have a big display / headphones / privacy
@Gargron
This also keeps the more immediate and positive type of interaction the norm. This isn't a forum where people are expected to dig up three year old threads to answer their questions, after all.