The term 'bending' means uniting two ropes. Some bends are quicker to tie than others, some are easy to untie. Some are strong (they do not reduce the breaking strength of the rope by much) and some are secure (the knot does not slip). Of course, the ultimate bend would have all of the characteristics above, but real life bends are always tradeofs between properties.
The bends on this page could perhaps be categorised as follows:
General purpose bends
The sheetbend is a well known knot. It is quickly tied, very easy to untie and does not jam, even when wet. The bad news are, that it is weak and may slip in some situations. Take care to tie the knot so, that both short ends are on the same side of the knot. Nevertheless, sheet bend is probably the best general purpose bend.
Taking two turns instead of one, renders the sheetbend into its double version. This is much more secure and perhaps a bit stronger. This is useful, when more security is needed than the simple sheetbend can provide. Then again, one can tie much more secure bends in the same time it needs to complete the double sheet bend.
This is one of the best bends a beginner could tie. It is very easy to remember, easy to tie and quite handsome. The ringknot is a bit hard to untie and is a bit bulky, but otherwise a very respectable knot. To tie: Follow the diagrams, which will create two overhand knots interlocked.
This bend is perhaps even more easy to remember, than the ringknot. The fisherman's bend is a secure and quick to tie, though maybe a bit weaker than the ringknot. It is very hard to untie after beeing loaded. If a beginner would like to learn a good bend, this should be the one.
A superb bend invented by C.W. Ashley, which is one of my favourites. It is easy to tie, very reliable, one of the strongest bends and very easy to untie. The only minus is, that it is a bit bulky, but the appearance is still quite attractive. To tie: Follow the first diagram to create two interlocked loops. Then pass the ends of the ropes down the center part of the knot. Pull on the ropes to set the knot.
This knot is useful, when the line has to remain in tension. It is especially handy when tying up parcells. To tie: Follow the first diagram, to create a loop around the black rope. Tighten the loop. Now, holding the red loop, pull the black rope through the loop as tight as you need it. Then without lifting the tension, make a half hitch with the black end around the red rope (diagram 2) and pull it tight. Now you can let go, the bend will hold.
The carrick bend is just the bend to use with wet ropes. It is not especially strong, but it is quite secure and most importantly, it does not jam and is easy to untie even wet. To tie: Follow the first three diagrams. This will create a handsome knot. But when you pull the ropes, the knot will capsize into its correct form (diagram 4).
The blood knot is one of the strongest bends. It does not reduce the breaking strength of a rope more than 5-10%. To tie: Place the ends of the two ropes besides, but pointing into opposite directions. Take one end and make two turns encircling both ropes. Then stick it into the middle of the two ropes. Repeat the process with the other end. Pull on the standing parts to tighten the bend. The ends can be trimmed short. Using rope, two turns are plenty, but anglers take more turns (4-5) when bending monofilament.