Thanks for posting these questions. The people who tend to see the posts on this forum are people managing Dataverse repositories and/or developing for Dataverse software. I mention this because you ask if people "use the Dataverse OJS plugin in your journal", but I don't believe journals using Dataverse read these forums. So if you're hoping that one way to get this info, about which journals use the plugin, is to survey journals, then asking in other forums would probably be best.
Information about the journals that use OJS's Dataverse plugin to deposit research data isn't something that we collect automatically. We haven't set up any automated way of collecting information about the OJS installations that enable or use the Dataverse plugin. This is something I've been interested in as well, so I wonder (more of a question for Dataverse developers) if this information would be in the logs and accessible using something like Splunk.
The survey approach is one way: What I'd do is gather the names of journals that have dataverses on Dataverse-based repositories, figure out which ones use OJS, and ask them if they use the plugin to deposit data related to their articles (hopefully they do!). For example, here's
the list of published dataverses on the Harvard Dataverse repository (which I also work on). I'd visit those journals' websites to see if they're using OJS (the webpage style gives it away, but sometimes I view source just in case). Then email editors of those journals who do use OJS to ask if they use the plugin. (On Harvard Dataverse, some of those dataverses are empty; they don't contain datasets, so they aren't using the plugin to deposit datasets. Also, the latest versions of OJS don't work with the Dataverse plugin, so some journals can't use the plugin because they're using newer OJS versions. See more about version compatibility details on
this plugin guide.)
Several other Dataverse-based repositories host journal dataverses, such as
UNC Dataverse, so depending on how thorough you need to be, you could consider all 33 repositories on
the map of known repositories. On the repository home page, you can filter by dataverse category for "Journal". There are two results on the UNC Dataverse that are not journals. I'd consider this a mis-categorization, and maybe there are dataverses run by journals that are NOT categorized as "Journal". So it might be worth asking individual repositories.
Please let us know what you think.