Dave Meltzer posted the following on wrestlingobserver.com:

Dana White has vehemently denied the big announcement has anything to do with Floyd Mayweather. The story as reported made absolutely no sense even though rumors did predate his retirement. As far as what it is, other than a network deal (which there are no rumors out on at all and those are very hard to keep quiet), I can't think of anything worthy of renting a place to tell all the employees.

So either...
1) Dana is lying
2) Negotiations fell through
3) The talks were just talks and nothing else.

We'll see on Thursday.