I was quite interested in the Google +1 feature, but for some reason, whenever I clicked on the icons, it always ended up not working and giving me the red folder(?) icon with Firefox (5). However, when using IE9, I had no issues.
It also occurred to me that whenever I was searching with the built-in Google search, it always showed me as not logged in, despite many attempts to do so. As a result, I never had the +1 next to my search results on google.hu.
I tried to delete just my Google cookies, then all my cookies with no avail. Looking at my cookie settings I noticed that my Firefox was not accepting third party cookies.
I thought this might be problematic when logging in at google.com and using google.hu so I checked the checkbox to allow the 3rd party cookies and voila!
Not only does google.hu stay logged in with the +1 visible, I can also +1 without any problems.