Using Mike Scott's old Netscape plugin SDK, I've been very successful in getting applications deployed with a variety of deployment options (thin client EXE, IE ActiveX/ActiveForm, and Netscape plugin). However, the Plugin SDK has been updated several times, and I haven't gone back to keep the original Delphi port up to date. Add to this mix the "other browsers" on the market that also need to be supported, and I was left wondering which direction to go.
The result was that I found the Netscape ActiveX plugin that allows ActiveX controls to be used inside Netscape-compatible browsers. So far, the results have been mixed, but I like the idea of having single-sourced code that compiles to the same deployment option (ActiveX), and let the browsers worry about how to handle it.