I wouldnt trust anything that Dana White says, his job is that of a promoter and he will say and do anything to get attention - including gradiose statements. Plus my personal beef with him is that he has kept UFC fighter salaries low so that they can cash in higher margins
Despite your personal issues with the guy (and you're certainly not alone when it comes to distrusting Dana White), he's not necessarily incorrect here. It's hard to evaluate the impact twitter had in the marketing world, but it is easy to see how it created new ways for brands to engage with their customers. Large success cases like Comcast or BA, and the fact that there's virtually no startup launching without a Twitter presence today to engage with their audience are good indicators of Twitter's impact.
I suspect twitter's given Dana and the UFC a huge vehicle to engage with people whenever they're not putting on events. It lets fighters, promoters, and the audience engage 100% of the time bi-directionally, and not just once every 2 or 3 weeks when the UFC is on the TV.
You coul argue facebook has a bigger impact then twitter plus i doubt that ufc fighters twitter pages reaches the vast majority of ufc fans - numbering in the tens of millions.
I think what Dana White loves about twitter is that he doesn't have to spend the millions of marketing dollars necessary for other communication mediums
Official fighter pay is reported to state commissions and can be found on many sites after the event. What is not disclosed, and is probably the lion's share of most fighter's income, is sponsorships.
I don't know who gets a cut of the PPV -- I suspect GSP and Silva and not many others. For the rest, their disclosed pay is in usually in the low 6-figures.
In the past there were a ton of stories about tactics used by Dana and the Fertitta's to keep overall fighter pay down. E.g. they wouldn't bring in fighters who were making big money at other promotions (such as Fedor and Overeem), for fear of setting precedents. They do seem more open to that now, though, as Overeem is in the UFC and Fedor might be soon.
Edit: Some examples from the last event (copied from Wikipedia):
Henderson - 250,000
Rua - 165,000
Wanderlei Silva - 200,000
Cung Le - 350,000 (total WTF)
Faber - 64,000 (including win bonus, plus Faber is a huge draw, another WTF)
And you have to remember that they rake in millions in ticket sales and more importantly pay per view deals, yet they keep salaries naturally depressed for people who are risking serious short-term and long-term injuries.
There is good reason why all major sports have a players association to negotiate he collective bargaining agreements with the owners