Besides this new linking feature, I don't understand how the hashtag feature should work in google+. If I try to search for "#android", what I get is a list of posts mentioning "android", without the hash. What I really want though isn't a casual mention of the word, but posts which were deliberately tagged "#android".
You can search for the full hashtag string (hash + word) in normal G+ search. I also noted a couple of days ago that the "Sparks" feature seems to have been revamped into a G+ permasearch / saved search. Your sparks now default to "Everything" searches (people, posts, Web, not sure about comments). And you can save any given G+ search to create a new spark.
Not sure if they're going to retain the name or if they're done messing with this feature yet, but it's one of the first things in a long time (well, a couple of months) that I've seen on G+ that struck me as useful and cool (granted, there's been a lot of under-the-hood tinkering and some interesting features released).
The whole Real Names / #nymwars situation has really, really dented my interest and faith in Google though.
Am I missing something?