Since we're open-source and registration is purely voluntary (http://pkp.sfu.ca/ojs/register
), all we can do is guess at the number of installations based on download statistics, Google searches, and usage of this support forum. Between OJS 1.x and OJS 2.x, we know of over 500 individual journals with more appearing every day.
We also run an installation of the PKP Metadata Harvester (http://pkp.sfu.ca/harvester
), to which OJS users can submit their repositories for aggregated searching and browsing.
Open Journal Systems Team