There are many places where you can make your work open access. These repositories, unlike for-profit platforms like ResearchGate and Academiia.edu, don't rely on capturing personal information to fund their operations. Here are some classic and new examples:
Founded in 1991, this site contains papers in physics, mathematics, computer science, nonlinear sciences, quantitative biology, quantitative finanice, and statistics.
A repository for social science papers (similar to SSRN, but not for profit.)
- Humanities Commons
Created by the Modern Languages Association, this repository and networking site offers all humanists a place to share and collaborate.