Are you familiar with web programming?
If you are not a programmer, basically it is a storage location on your PC managed by the browser (Chrome in this case). So the settings are only available to the one PC. Each PC you have with ezLinkPreview has its own set of options stored on that PC and there is no synching between them. I believe google is working on a way to sync extension settings between PCs, so at some time in the future I may offer that as a feature.
I hope this answers your question,
Erik