If a reader pays a subscription to access the article through the journal, the author(s) are generally able to share the Author's Accepted Manuscript (post-print) and the Author's Submitted Manuscript (pre-print) online.
If a reader can access the article free of charge through the journal, especially when an Article Processing Charge (APC) was paid, the author(s) are likely able share the Version of Record (VoR) online.
It depends. Permissions for self-archiving/posting works online is highly dependent on the publisher. Authors are encouraged to check their publishing agreement and/or reach out to their publisher to explore whether they can self-archive their book chapter online.
It depends. Authors who do not sign a publishing agreement are likely able share their work online. Authors who do sign a publishing agreement should review the agreement and/or contact the conference to determine sharing options.
Authors/Creators are likely able share their work online.
Have you or your co-author(s) signed anything, such as a publishing agreement, that gave away rights to the work? Creators have rights to copyrightable works unless they agree to give them away. Rightsholders can exercise their rights to share their works online. Note that works licensed under Creative Commons licenses, and many other "open" licenses, may be shared online by their authors.
Agreements that deal with copyright and permissions usually contain information on what rights each party is entitled to, such as whether or under what conditions an author may share a work, or version of a work, online. As an author, here's how to check your authors' rights:
Note for Graduate Students - It is recommended that students who be building their theses, dissertations, or reports (ETDRs) based on published work that they check the policies of a journal before they publish. Graduate students will specifically want to ensure that they will retain the right to use the work in their ETDR. Those who do not secure such rights beforehand risk not being able to include the published work in their thesis or dissertation.
If no or limited information is available on a publisher's or organization's policies regarding sharing work online, it may be helpful to contact them directly and explore if or how a work may be shared. It has become an industry standard for journal publishers, and an emerging trend for some book publishers, to have policies that allow authors to share their submitted manuscripts (pre-prints) and accepted manuscripts (post-prints) following an embargo period. Encouraging publishers who have not yet adopted online sharing policies to develop such policies will help future authors better understand how they can legally share their work and help increase their impact.