Twitter had initiated granting of datasets some time back (now closed)[0] on the merits of a short proposal. The number of groups who eventually got access to the data were very few[1]. I hope in the future they increase the number of grants.
Yes, I am pretty sure this article is just rehashing the Twitter grants (I believe there were only 6 to 8 rewards), rather than announcing full open data to any researchers (thereby making the title misleading).
[0] https://blog.twitter.com/2014/introducing-twitter-data-grant...
[1] https://blog.twitter.com/2014/twitter-datagrants-selections