The answer, unfortunately, is that we still don't know, but here's a quick recap of some relevant facts.
1) Trump is subject to financial blackmail. He would pay to keep his financial records a secret, so if Putin could acquire any financial records, Putin would be able to extract something from Trump.
2) Trump, by the admission of his idiot children, has had a history of business and financial dealings in Russia because no American bank is stupid enough to loan him money.
3) People in Trump's immediate orbit-- Flynn, Manafort, Don Jr., Papadopoulos, Page, Sessions and more-- have taken a lot of meetings with the Russians. The Russians have made clear attempts to get inroads into the Trump organization by offering help in the 2016 election.
4) The Russians actually did intervene with the clear goal of helping Trump.
5) Everyone in Trump's orbit has a pattern of lying to investigators and to Congress about how much contact they had with the Russians.
6) Trump has done everything possible to obstruct any investigation, including firing the Director of the FBI, and he has admitted that he thinks that the AG's job is to protect the president, which was why he was pissed about Sessions's recusal (which he probably violated by firing McCabe, but I'm messing up my numbering system).
7) Trump refuses to criticize Vladimir Putin in direct terms, regularly denies that Russia had any role in meddling in the 2016 election, and generally acts as though Putin is his hero, idol and father, all wrapped up in one. Given Trump's creepy attitude toward Ivanka... well...
OK, all of that looks bad. The Steele dossier says that Putin has blackmail material, though. So, a) what has Putin gotten from Trump, and b) the sexual blackmail part?
"The Trump administration" just imposed some mild sanctions on Russia for the election meddling. Note the quote marks. Why the quote marks? The administration is not simply Donald Trump. Suppose Putin does have blackmail material on Trump. Trump's position, then, is analogous to that of an undercover cop. The cop isn't actually working for the mob, or whoever, but he must participate in the commission of crimes to maintain the cover. Trump can't give Putin everything, but he has blocked sanctions for a while, and been about as deferential as he can be.
If Putin has blackmail material on Trump, it would be used for something under the table anyway.
This gets into non-falsifiability, and I'll get to that soon.
Then, there's Stormy. Trump is susceptible to sexual blackmail. He, through his lawyer, has paid hush money to a porn star, and he is going through a lot of legal maneuvering to try to keep her quiet. Probability that she is the only one with sexual information about him that he really wants kept under wraps? Epsilon. (Remember that epsilon is the Greek letter we use in mathematics for numbers arbitrarily close to zero because in statistics, we don't refer to any probability as zero). How hard would it be for Putin to find some of this information? Not very. Trump is stupid and careless, and the Russians have a long history of this. Golden showers? Realistically, probably not, but sexual blackmail for Trump? With the Stormy Daniels thing? The likelihood that Putin has something, either financial or sexual on Trump...
He's stupid, careless, corrupt... As I have written before, the only question for me at this point is whether or not Putin needs it. Trump is so obviously awed by Putin that it is more effective to use that emotional manipulation than to turn to blackmail, thereby turning Trump into an enemy because you don't want Trump to feel like he is being controlled. That's still where I come down on this. Putin probably has dirt, but probably hasn't used it because a) he hasn't needed to, and b) as soon as you use it, you turn the other person into an enemy, and Trump worships Putin. That's more effective control than blackmail.
Now, let's look through this process. This isn't social science. Here's how social science works, even in the limited world of small-n analysis (when you have a small number of cases). You have a "dependent variable," which is the thing you are trying to explain, like treatment of Russia or other generally hostile foreign powers. Then, you have a set of "independent variables," which are the things that could potentially explain the "dependent variable." Those could include things like the potential for blackmail, level of personal affinity for totalitarian rulers, and level of basic competence.
In small-n analysis, what you do is look for a set of cases that are as similar as possible in every respect except for the dependent variable, and the one variable that you are studying. So, if I want to know whether what's going on is blackmail, in social science terms, then I want to compare cases-- presidencies-- that are similar in terms of personal affinity for totalitarian rulers and basic competence, but different in terms of potential for blackmail, to see if those other cases-- presidencies-- are less deferential to hostile foreign powers.
That's the social science approach. It is different from the legal approach, and lots of other approaches, but that's how small-n social science analysis works. In large-n studies (my preference), we use similar reasoning, but we can do a lot more, make more precise probabilistic estimates of the patterns we are observing, control for more variables, etc.
We aren't in that world, though. More importantly, we are in a world in which Donald Trump is a completely unique case. We haven't had a president so obviously susceptible to so much blackmail before. Sexual blackmail? Arguably, a bunch of presidents would have been susceptible to some of this, but not on the scale of Trump, who is a serial rapist. Given that, though, and given that it is public knowledge that he is a serial rapist, I really want to know why he is fighting so hard to keep Stormy Daniels quiet. How much worse can it get?
Just throwin' this out there: he's impotent, has a small penis, doesn't know what he's doing in bed, etc. Is that worse than being a rapist? Hell no, but it would be to Trump, and that tells you something about him.
What about the other independent variables? Has there been another president so completely in love with totalitarian dictators? Nope. That's just Trump. Has there been another president as completely incompetent? Nope. Trump.
There's the problem. Small-n analysis breaks down if we can't find a comparable case. We're stuck here, unless there is some revelation of details that we aren't observing, but we can't rely on the claim that everything happens behind closed doors. Basic rule of science: you can't base your arguments on "non-falsifiable" claims. Claims must be falsifiable, meaning that if they are wrong, you must be able to find evidence that they are wrong.
We're stuck here.
This looks bad for Trump, though. He is clearly susceptible to both financial and sexual blackmail. Putin knows how to acquire and use that information.
Even if Putin has nothing now, though, I will say with certainty that he is working on it. And that's dangerous.