Without the report, though, can we really draw such conclusions? Here's what we do know:
It has been clear for months that Mueller was pursuing possible conspiracy angles late into his investigation. Former Trump campaign chairman Paul Manafort was revealed to have lied about sharing polling data with an associate with alleged ties to Russian intelligence. And a top Mueller team lawyer said the episode went "very much to the heart of what the Special Counsel's Office is investigating", according to a transcript of a hearing between Mueller's team and Manafort's attorneys.
Longtime Trump adviser Roger Stone was also recently indicted on charges related to his outreach to WikiLeaks, which disseminated documents the Russians had hacked. His indictment said that "a senior Trump Campaign official was directed to contact STONE", which was a curious and unusual use of the passive voice that didn't indicate who did the directing. There was plenty of thought that person might be Trump. The president denied it.
Ultimately, Mueller didn't charge Stone or Manafort with conspiracy, even as he charged them with other crimes. And it appears Mueller won't be indicting anyone else within Trump's inner circle.
It's worth noting that collusion (which is a blanket term Mueller's team has used for a number of different types of conspiracy) is a crime that's very difficult to prove. Even the publicly known links between the Trump campaign and Russia have been somewhat tenuous, as Philip Bump has rightly emphasised for months and months.
This brings us to Trump. According to existing Justice Department guidelines, a sitting president cannot be indicted. The fact that Mueller isn't indicting Trump tells us nothing about his conclusions about the president personally. But the fact that none of his campaign aides or advisers are going to be charged with conspiracy does suggest Trump won't be accused.
Trump could still theoretically have collusion-related problems, particularly if (a) Trump directly colluded or (b) someone else colluded on his behalf but for some reason is not being charged with it. Perhaps they co-operated and got leniency, for example. Or perhaps Trump publicly asking Russia to steal more of Hillary Clinton's emails could amount to collusion by itself. It's possible, but it seems unlikely.
In that way, Trump and his supporters can rightly be encouraged by Friday's news.
It does not mean, however, that Trump is out of the woods. For all the focus on collusion, it was never the most problematic aspect of Mueller's investigation for Trump personally. The collusion narrative was the sexiest one for the media to cover (and the one Trump pushed), but obstruction of justice was always the more likely crime Trump had committed.
Friday's news tells us next to nothing about whether Trump's myriad questionable actions vis-a-vis the Russia probe, starting with firing James B Comey as FBI director, might land him in hot water. Mueller's investigation has also sprouted other probes in which Trump has been implicated (but not directly accused of criminal activity) in Michael Cohen's campaign finance violations, and in which Trump's finances and entities are being scrutinised.
Trump, to his strategic credit, kept the focus on "NO COLLUSION" throughout, perhaps knowing it was unlikely it would ever be proved and that the lack of proof could then be used to undermine whatever else Mueller finds on him. "They didn't find collusion, so they looked for a bunch of other stuff" is already an argument the Trump team has been making. Given the intense focus on the topic, it's important to emphasise how much Friday's news indicates Trump was probably right - at least in Mueller's eyes.
But it's also worth noting that Trump doesn't seem to be celebrating quite yet. In fact, he's been very quiet. Perhaps that's because he has decided to let other people draw these conclusions rather than step on his good news. Or perhaps it's because he knows this is hardly the end of his troubles.
