Directories have been SEO levers for a long time – black hat just as pure white hat seos do still use them.
The constraints of directories is that each description, which must be expanded to a minimum (say 300 words), must be unique.
If you entered the site on 1, 2 or 10 directories, it can be done manually (although after the 7th description we start to get tired, right?)
When you reachtens or hundreds of directories, this isn’t just human.
How do you honestly keep in mind the 37 unique descriptions already written, to write a 38th?
How does one ensure that the 103 versions are actually, every each one, unique ? How does one measure it?
It is inhuman, and that is why the spin syntax with its brackets can encode all these versions into a single text, the master spin.
With this syntax, it is easy to view and compare different versions, and to quantify the number of different versions that really can be achieved.
One can certainly outsource writing a master spin for a directory description. It will cost you something like $200 for a few hundred variations.
You can also use Spin Synth and chop, assemble several modules, integrate (possibly) an RSS feed of your site to retrieve the titles of your articles, mix (if needed) with a database of products, enhance some phrases, all varied in structure, and you will end up with a ready master spin.
Master spins, allowing you to get thousands of different copies, have emerged with Spin Synth… this is too easy!