Until now it’s been possible to track referral traffic from Google Plus simply by filtering to ‘plus.google’ in the referrals report in Google Analytics or your favourite analytics package.
This changed on December 3rd when Google started redirecting most traffic through a new subdomain, plus.url.google.com.
If you want to see referrals from both plus.google and plus.url.google in the same report, set up a Matching RegExp Advanced filter to ‘plus.*google’
This should filter to include all Google plus subdomains.
Something else we’ve noticed is that traffic referred from Google Plus appears to have increased in the last week for the first time ever after a continuous decline.
This is probably a side effect of the change in tracking …or could they finally have reversed the trend and started to see some genuine growth?