When you have already said yes to having a webapps page it persists in asking again
I've got webapps page for G+ installed for @gmail.com domain and only that each time I go to plus.google.com it still asks me every time even though I already have it installed.
I can go to the envelope indicator and see the Google icon, clicking on it opens up a separate window and again the banner still asks do I want to set up webapps for this.
DistroRelease: Ubuntu 12.10
Uname: Linux 3.5.0-16-generic x86_64
Date: Mon Oct 1 10:01:26 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
UpgradeStatus: Upgraded to quantal on 2012-09-08 (22 days ago)