The following question is raised in a comment by OP:
This "new" score/answers bars have never appeared on my summary page before... so I thought it was related to site analytics. How does one change the "Next tag badge", or is it static?
You didn't see this before because the site lets you track either a tag badge or the next privilege to be unlocked and I'm pretty sure previously it was tracking privileges in your profile, something like this:
By reaching 25k, you have unlocked the last possible privilege, viz. 'access to site analytics'. Since there is no more privileges to track, the system has switched to tracking a tag badge instead and picked virtualbox for being the most likely next in the queue (as per some algorithm).
As far as I know you cannot disable this feature. You can however pick a different tag to track by clicking the cogwheel next to tag being tracked currently (cogwheel next to virtualbox as in your screenshot).