As with any other copyrighted work, other scholars can make fair use of your scholarship in their own research. Since you own copyright over your work, however, you can decide whether you want to license your work beyond what fair use already allows.
There are several reasons why you might wish to license your work. One reason could be to contribute to knowledge building and scientific or artistic progress. Certainly, people can already make fair use of your material, but by licensing it you are encouraging thus facilitating their use of your work. Another reason might be that making it easier for other people to use your material could translate into their using your work more often--which means being cited more often, and increasing your scholarly impact and profile.
If you do wish to license your digital scholarship, one option is to use a Creative Commons license. Creative Commons licenses allow copyright holders to prescribe the scope of uses (beyond fair use) that others are able to make of their work--while still retaining copyright ownership for the creator (that is, you are licensing your work for others to use, not transferring your copyright ownership).
Just be sure to check whether you have entered into licenses, employment or other agreements, or received funding and grants that control how and whether you can or must license your project. License your work according to the terms of these other agreements or provisions.