If you click the options arrow on the chat feed (next to your name/status), there is a "Privacy Settings" option that allows you to specify which circles can chat with you.
fwiw, you can also specify which circles are in "Your circles" (the ones you broadcast to) and which circles you are just following in the G+ settings (https://www.google.com/settings/plus).
i don't know if i'll have time to finish anything, but if you would like to send it to me (email in profile), i'd be interested in looking it over and trying it out.
I think it would be more interesting if the number of requests were normalized based on either number of google users or the population of that country.
1. On a first glance the interface is a little overwhelming, and I am not sure where to go/what to change first. Have a single column of options that can be expanded/condensed accordion style (think the Mac MS Word formatting sidebar).
2. Buttons produced are only a single image. It would be nice if multiple images/sprites were created (that is, a single image file, with multiple images). The additional images would enable hover and on click capabilities, providing a user with visual feedback that the image is indeed a button, and that it is working. That being said, you may also need to include the relevant CSS necessary for a user to select the correct sprite in each situation.
3. Having the Undo/Redo on the top right seems a bit unnatural. (I didn't even notice these options at first; moving them to the top left may be better?) You might also consider using the standard arrow icons for these options with a text description on the bottom or on the right
4. Other people have already mentioned this, but additional fonts and a color picker would be very useful.
5. The site's layout requires a fairly wide screen. When I don't have my browser window maximized, the layout gets kinda messed up (input boxes flow to the next line abandoning their label).