Jeanette, the TDoV tends to be a pretty small event. Visibility is not something most of us aspire towards, but the event is being celebrated in a few places to both remind the world that we are here and are just human beings, not to be feared, and more importantly in my opinion, to remind those that remain hidden away, even from themselves, that times are slowly changing, and it is possible that they may find their true selves someday soon.
Rachel Crandall founded the TDoV in 2009 as a reaction to the lack of LGBT holidays celebrating transgender folks, from frustration that the only trans 'holiday' was the Transgender Day of Remembrance where we mourn those lost to violence in the past year.
You can read more about the International Transgender Day of Visibility here:
http://www.transstudent.org/tdov