eFax had some patents that it used aggressively for a long time to shut down competitors, though it looks like the main one expired recently. https://news.ycom

eFax had some patents that it used aggressively for a long time to shut down competitors, though it looks like the main one expired recently. https://news.ycombinator.com/item?id=16660890 https://news.ycombinator.com/item?id=16660890