I had seen on here people wanting urls to automatically log people in, but the plain text would be a serious security issue....
I'm gonna add my 2 cents - what would be great if there could be a sign-in page and the server could a have a seed that changed on a daily basis or a per set amount of time from when the user logged in say 24 hours etc
That seed geneteres a hash for the user so all during that time the seed was valid the user urls would include the hash and could automatically be used to authenicate them (ie the url links would have the hash right included so all download managers and streaming software would know its user: bob) It could be as simple as server master seed + rotated seed + username to generate the final hash then just add to the link &id=(hash here) - doesn't have a good hash then they are just a guest
Again the seed value changes by some set amount of time, that way those url are not valid the next time it rotates