Twitter has so far not made public any of the restrictions that will be
placed on developers who use the firehose, or the kinds of agreements that will need to be in place before such access is granted. I've asked for clarification on the Twitter API developers' mailing list, but so far have received no answer other than, "There will be further announcements about Streaming API access early next year."

Moreover, as of just a few days ago, their position is still:

"The Firehose is not a generally available resource. Few applications
require this level of access. Creative use of a combination of other
resources and various access levels can satisfy nearly every
application use case."

"The other levels of Streaming access are not only considerably more cost effective for all parties, they are also (nearly) sufficient for the vast
majority of applications."

"The filtered and sampled streams are where virtually everyone will wind up."

And on location-based processing:

http://apiwiki.twitter.com/Geotagging-API-Best-Practices

"Users will have less interest in providing their current location
if they are unaware of the value on the other side of the transaction.
You as an app developer should always try to provide immediate value to
incentivize the user to provide the information. This can come in
various forms -- showing nearby tweets, narrowing search based on the
user's location, promoting user discovery based on proximity to the
user, etc."

I agree - opening up the Firehose and the Mixer acquisition are a
"strategic move". But not all of the 50,000+ "developers", if there are
indeed that many, are positioned to participate with solid fundable business plans. I'd venture to suggest that there are more like perhaps five to ten, and two of them - Microsoft and Google - are already in the hunt. And that's not even counting the marketing force that is Facebook.

Twitter is a small company - there is no way they can "manage" 50,000 "partnerships". They will need to focus, focus and focus some more! And that's going to mean playing favorites based on solid business decision processes and realistic partnership agreements. The chaotic growth that's characterized Twitter in 2009 can't be sustained.