does the Editor not review all those pending in the same category at once or is it just on a site by site basis, regardless of category?
No, and no. You clearly have a completely wrong notion of how the ODP works, as both of these are absolute nonesense, literally impossible.
The editor picks which sites to review first, based on criteria known only to him -- nobody else has the right to even ask! And the volunteer editor can stop reviewing sites whenever he wishes. So ANY generalization, any generalization at all, about how "THE editor" works -- is false. Editors have many ways of working. Most active editors work in different modes at different times.
Secondly, what YOU probably mean by "sites pending" is probably "sites submitted." If this is what you meant, this also is not a concept that has anything to do with the Open Directory. All sites on the internet are always pending. Editors are expected to use creativity in finding sites -- to look for sites in multiple ways, to avoid the bias that inevitably comes by taking all of your samples from the same point. The "site suggestion" pile is just one way, and not the most important way, and not the highest priority way, for editors to find sites. All it is is a reminder that a particular site hasn't yet been looked at. It is not a compulsion to look at it!
You can see how absolutely nonsensical it would be for any editor to look at the whole internet at once. It never happens. Being human, we look at one site at a time. (Well, some active editors may open several browser tabs and sort of look at several sites at once. But ... the whole internet? Get real!
But "on just a site by site basis regardless of category" is equally nonsensical. It sounds like you're thinking of editors as robots on an assembly line. The submittals flow in. Each editor takes the next one. But there is nothing like that either. Submittals go to the category where you submit them -- anything else would be absolute nonsense. Assuming you're going to treat ME like one of these robots: what good is it for robot-h1733 to take the "next submittal" if it happens to be a Chinese site? What good is it for the next site to be reviewed by robot-h1733, if it happens to be a fan site for contempop music or international-socialist politics? Clearly that's not a sane way of running even a sweatshop, let alone a volunteer directory.
Well then, what really happens?
Sometimes editors find a truly exceptional site that intrigues them, and look for a good place to put it. But that's not the most common mode of operation (and the unreviewed queue is the least likely place to find such a site.)
What happens much more often is, editors pick a category to work in, and then look for sites. One place that we can look for sites (but only one, and by no means the highest priority or most important) is the "site suggestions for that category". But how or in what order sites are searched or reviewed, is up to the editor.
The result is, each editor works in the way that pays off best (in satisfaction or sense of accomplishment). That way, the project is likely to get the maximum amount of accomplishment possible from each editor. That way, the maximum total number of sites get reviewed and listed, and the average time from "site publication" to "site review" is minimized. (There is nothing significant about time of "site suggestion", so it doesn't enter into this anywhere.) This way, the sites that get reviewed are the ones that are most interesting to our sampling of surfers (that is, the editors themselves), so the work we do is most useful for our customers (who are also surfers.)
But ... this way nobody ever knows what sites will be reviewed next, nobody ever knows when a particular site will be reviewed, and it is possible that some sites (even suggested ones) will continue to be overlooked for an indefinite period.
This isn't a problem, because the ODP is not about promoting particular sites, and doesn't offer site promotion services. In fact, it is itself an inestimably great advantage. Consider this. What's the biggest problem on the internet today? The answer is obvious. Affiliate spam. There are people whose entire purpose in life is to subvert whatever internet indexing systems there are, in favor of their own spam (and against the real sites, as well as other people's spam.) Any system, once discovered, will be quickly attacked from a thousand directions. So the ODP's defense is: no system.
It is left as an exercise to the reader, how the spammers could successfully attack and subvert the following mechanisms:
(1) All submittals guaranteed a review in, say, 10 to 11 months. No (or almost no) submitted sites reviewed early, no submitted sites take longer than that.
(2) Editors constrained to review only submitted sites, or to review submitted sites before any others.
(3) Within a category, editors required to review sites in submittal order.
There will be no practical check, since there would be a race to see whether the spammers crashed the ODP servers with their submittal spam before all the editors quit. I'm betting the editors would win, but it would be a very very close race.
