You may try https://www.researchgate.net/
But I am not sure what their policies are.
Since I wrote this information, two people downvoted the answer, not
saying why.
But this answer is factually correct. You can make scientific papers
available through Researchgate, and probably some that are not too
scientific. I have done so, though I would not choose Researchgate as
my primary publication medium (all of my papers there were first published on
some other venue).
Some people do get my papers through Researchgate, so it does fulfill
the dissemination purpose to some extent. I am also told by
researchgate about citations of my papers, so that I can see what
people make of them, and I can get some of the citing papers through
Researchgate. I do not really use Researchgate professionally: I am
retired. But then, the question was also for informal availability on
the web.
I know that some people do not like Researchgate for various reasons,
and possibly for opposite reasons. Mainly, they seem to lack
resources and many of their weaknesses do not get corrected. But they
do not ask for money as does Academia.edu. So I use them for what they
have to give, and try to be tolerant with their failings.
One of the major problems is, as remarked in other places, that they
do not manage well authors that have the same name. I am particularly
aware of that because my name is somewhat common. But then
Researchgate is not a reference medium.
So my advice is to be very precise on the paper itself about your name,
affiliation, and any other public information that will identify you
as a single person (using your social security number might work, but
is not advised). If the paper appeared somewhere else, try to also
give that information. And remember to be careful with copyright, and
to preferably know what you are doing in this respect (even when you
choose to disagree with some publisher).
Last remark for downvoters. My information is factually correct. So
you are really criticizing the operation of Researchgate, even though
all the user want is to make his papers accessible. It would be better and more useful
to explicitly state, however tersely in a comment, what your
objections are.