Daniels alleges that since "David Dennison" (aka Donald Trump) never signed the non-disclosure agreement it's now null and void, and she's free to talk or write about their nearly year-long tryst.

Another interesting tidbit here is that she also alleges that Michael Cohen forged her signature on an e-mail he sent out.

This could get very interesting in the coming weeks.

Source: NBC News

Adult film star Stormy Daniels sued Donald Trump Tuesday, alleging that he never signed the nondisclosure agreement that his lawyer had arranged with her.

The civil suit, filed in Los Angeles Superior Court and obtained by NBC News, alleges that her agreement not to disclose her "intimate" relationship with Trump is not valid because while both Daniels and Trump's attorney Michael Cohen signed it, Trump never did.
...
The "hush agreement," as it's called in the suit, refers to Trump throughout as David Dennison, and Clifford as Peggy Peterson. In the side letter agreement, the true identity of DD is blacked out, but Clifford's attorney, Michael Avenatti, says the individual is Trump.

Each document includes a blank where "DD" is supposed to sign, but neither blank is signed.

According to the lawsuit, which Avenatti announced in a tweet, Clifford and Trump had an intimate relationship that lasted from summer 2006 "well into the year 2007." The relationship allegedly included meetings in Lake Tahoe and at the Beverly Hills Hotel.

Here's a link to the lawsuit, here, from her attorney's tweet earlier today.

UPDATE: (Karoli) Here's why it matters so much: