Before discussing options for exposing your content to Zotero, ask yourself “Do you want users to capture data about individual pages of your site, or do you want them to capture information about a resource, or several resources, discussed on that page?”
Let's clarify this with two examples. Consider an article in an online newspaper and a bibliographic record in a library catalog. In the first case one wants to get information about the page the user is looking at; information about the specific article. In the second case, the page in a library catalog, the page itself is uninteresting; your user is interested in information about a resource described on that page. In this case, your user is interested in a specific resource discussed on mentioned on the page, not the page itself.
Many of the strategies discussed below can fit either case, but it is important that you identify exactly what you want users to use Zotero to extract from your site.