There are expert SEOs and Link Builders that are doing directory submissions. There are 4 kinds of directories here: pay-for-inclusion, reciprocal requisite, free and niche directories. And there are of course specialist in each one of these. There are about one thousand free SEO welcoming general directories, a list of these and a submission service can be seen here. As for post in reciprocal directories there are both broker and non-brokers.