To fully participate in the collaborative note taking and view presentations, participants simply need an internet connection and a modern browser.
See Browsers and Plugins for specific browser information and a link to the Lucid System Check page.
That said, we've used Lucid Meetings during face-to-face meetings and at times when other people could only join by phone.
In these cases, meeting facilitators and note takers take responsibility for capturing notes on behalf of those who aren't logged in.