I've been an active player on SSRN since it started and have used it countless time to find research sources. So I was taken aback to learn that it's been sold to Elsevier.

The sale has generated a lot of negative Twitter chatter:

@anseljh I want SSRN to survive this transition. But I'm doubtful. Elsevier would be wise to make a binding public commitment to openness. — Mark Lemley (@marklemley) May 17, 2016

With Elsevier having bought SSRN, we'll see how many restrictions Elsevier will impose before the professors bail. — Orin Kerr (@OrinKerr) May 17, 2016

When Elsevier bought SSRN, the valuable assets weren't the servers and disks, they were the papers we uploaded. — matt blaze (@mattblaze) May 17, 2016

What's the big deal you ask? From my perspective, I don't begrudge SSRN's backers' decision to sell. They're entitled to a reward on their expenses, time, and effort. But SSRN's ethos was supposed to be about open access, which makes one wonder if they could not have found a buyer whose business track record was less anti-open access?

Paul Gowder rightly complains:

Elsevier is the most notorious of the giant for-profit academic publishing firms. They charge truly astonishing subscription costs for academic journals, even though they aren’t obliged to pay authors, referees, etc. For example, one of the more egregious of their yearly subscription rates is the Journal of Nuclear Materials, which will cost libraries $7,442.14 for an electronic subscription, or $11,164.00 for a print subscription. (Full disclosure: I cherry-picked that one for impact.) No, those numbers are not typos. If your institution doesn’t have a subscription, a single article download will cost you $40. Of course, as an author, you can always choose to make your paper open access. The fee for doing so? $3,500. Apparently some authors actually pay these fees (or, more to the point, have them paid by grant agencies), because the professional validation of peer review is so important for academic careers that it’s worth it to get the stamp of a professional journal on one’s work even if it means that money gets flushed down the toilet for the privilege of getting to post one’s own work on the internet.

Indeed, Elsevier is so hated in the academic community that there is actually an online petition with over 16K signatures in support of a boycott of Elsevier:

Academics have protested against Elsevier's business practices for years with little effect. These are some of their objections: They charge exorbitantly high prices for subscriptions to individual journals. In the light of these high prices, the only realistic option for many libraries is to agree to buy very large "bundles", which will include many journals that those libraries do not actually want. Elsevier thus makes huge profits by exploiting the fact that some of their journals are essential. They support measures such as SOPA, PIPA and the Research Works Act , that aim to restrict the free exchange of information. The key to all these issues is the right of authors to achieve easily-accessible distribution of their work.

SSRN's response to all of this is basically "trust us":

@mearest This is a good thing! But you don't have to take our word for it. Just keep your eyes open as things develop in the coming months. — SSRN (@SSRN) May 18, 2016

But we'd be more inclined to trust SSRN's management if they hadn't sold out to the worst of the legacy publishers:

Elsevier ... is infamous for restricting the flow of scientific information so it can sell research papers for as much as fifty dollars a piece, generating profit margins of thirty-six per cent and netting the company billions of dollars in revenue annually. The company has fought legislation designed to open up academic research, offered scholars money to file positive reviews, sued libraries for oversharing, and allegedly published fake journals on behalf of the pharmaceuticals industry.

But even in the unlikely event that Elsevier proves to be on the side of the open access angels, I'd still be worried. Since Elsevier took over Mendeley, for example, it's storage prices have jumped significantly. As a place to stash research, DropBox is much cheaper and, in many ways, a lot easier to use. In my experience, Mendeley's research management tools are not very user friendly, it doesn't handle Bluebook legal citation practices real well, and doesn't easily interface with Word to add references to a text. It may well be true that 5 million academics use Mendeley, but for the life of me I can't see why.