That's a pretty cool sight, although some of the classifications confused me.

For example, suppose I've got two ropes that I want to join together near the ends. I need a splice, right? And there is a "splicing" category...but the "splicing" category only contains one knot for joining two ropes end to end. All the rest are for joining a rope to a non-rope, or joining two non-ropes via a rope, leading me to wonder if I misunderstand what "splice" means.

There are plenty of splices on the site for joining two ropes near their ends, but they aren't in "splicing". There is the Double Fisherman's knot, which is described as being for securely joining two ropes of similar size, which is listed under "climbing" and "scouting". There are similar cases of splices in "fishing" and "boating" and some other categories.