Thanks Jono for condensing some of the discussed points from the hangout.
As you already have done, using the general hashtag #XPRIZETT on one of your tweets, the general hashtag will enable not only for distant XPRIZE Think Tanks to gain awareness about others activities, and be able to get into the conversation, share the info to friends living in these areas, additionally this offers the opportunity to tie together the global activities and being visible for "newcomers" and other stakeholders (as potential sponsors).
I have created a "virtual event" on Eventifier (which is partnering with us on other fields of business).
Have a look at it here: http://eventifier.com/event/XPRIZETT/
For the moment being there is not much to be seen (besides Jono's first tweet using the mentioned hashtag), and visibility of this event page is for the moment for next 14 days (to extend this either sponsoring, crowdfunding or an arrangement with Eventifier will be needed - rather a minor challenge compared to what we are passionate about)
Some ideas on building traction for XPRIZE Think Tank visibility around it:
Create specific hashtags for each XPRIZE Think Tank, e.g. #XPRIZETTDresden (this I would add to the hashtag list that Eventifier should "catch")
Tag pictures from a XPRIZE Think Tank meeting with hashtag
... just some first ideas to exponentially accelerate with given technology
What do you think?