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.
I was worried this wouldn't work very well for them, because Google always wants to put "relevant" stuff first and "most recent" (the way Twitter does it) later. So from that point of view, they could never match Twitter for latest news. But putting the latest news on top of the relevant ones is a pretty smart way to do it, rather than just relegating it to another tab.
Also, danmaz74 has a point. If you search for #Android, you should see only posts containing the hashtag "#Android" and then sort them out by relevancy, and so on. But 100% of the posts should have the hashtag in them if that's what the user was searching for. For non-hashtag queries they can use their regular relevancy algorithms.
And most recent is always so terribly relevant in Twitter feeds ....
I'd like to see some sort of ranked system. Google does really good for relevance, but timeliness also matters. Some sort of score where a relevant / trusted but not quite-so-recent post gets promoted on top of spambots would actually be a Good Thing[tm].
What's the motivation for building Google+? What problem does Google think it is solving? What does it think it is contributing to the world with Google+?
Am I missing something?