Google+ used to be a great source of dofollow links, but it looks like the party has finally come to an end.
When Google+ first launched, all of the links from the site were dofollow. This included all links from your posts, all links on your profile page, and all links in your bio and links section of the About page.
This started to change in February when Google+ nofollowed the links under the “Links” section of your profile page. At this point, any links that you included as part of your bio under the “Story” section were still dofollow.
Then in March when Google+ first launched larger images for shared links, they removed most of the dofollow links from posts in addition to making the images larger.
Posts shared on Google+ pages continued to have dofollow links in them within the page itself, but this was changed in April. The last holdout for dofollow links were the links in the “Story” section of your profile, but as of this week those links seem to be nofollow as well.
As of today, it appears that Google+ has followed the path of other social networks such as Pinterest (which used to have dofollow links) and nofollowed all their external links. Internal links that point to your profile or page are still dofollow, so there is still value in building up the authority of your profiles within Google+, but it is no longer possible to pass that link equity to external sites.
It was fun while it lasted, Google+. At least there’s still Tumblr as a source of dofollow links.