Maybe it would be more clear as:
"The first annual Free and Open Source Software Yearly conference"
Instead of:
"The first Free and Open Source Software Yearly conference"
Putting "annual" in the title makes that meaning / context more clear to me.
"The first instance of" or so might be more clear but, yeah, the catchiness degrades with every attempt at making it clearer. One might even be lead to think that "Free and Open Source Software Yearly" is not an amazingly unambiguous name to use in a world with fosdem, t-dose, and probably others.
But here's a real solution (though I don't think it was a problem needing to be solved):
"FOSSY: the Free and Open Source Software Yearly conference, year 1"
Yeah but the F is FOSSY stands for First. Either they change the name next year or it doesn't make sense.
As someone mentioned Fossdem, the is also the LibreGraphics thing, and perhaps some other smaller ones.
The name is IMHO a very poor choice. My suspicion is they actually thought this would be a first of its kind, but that would mean they are not the right people to do this.
It clearly stands for "Free", where do you get that idea?
>>The first Free and Open Source Software Yearly conference
Sure the word "first" is in there but it doesn't even have the capital F like Free....
Bows head in shame....
(...Non-Discriminatory)