Basically, it helps managing all your affiliate links under one single dashboard, making easy to add them every time you create new content. CPUs most certainly give you access to individual bits. You can AND a value with a mask that has only a single bit set, and then compare that result to zero and make a decision. Some architectures have real instructions to do exactly that. You can also bit-shift by 1 or 3 or any number (just about - but you're definitely not limited to multiples of 8 that you seem to imply).