There's probably hundreds or thousands maybe even millions of different directories on the web, a lot of which you can submit your site for free. What do you think about submitting to these small time directories? Will they produce extra traffic?
I don't think there's much evidence to show th t they're effective. At best they act as portals to the biggies. My greatest concern is that you will be inadvertently labelled a paid ranker in which case you will be penalised big time. Google and Yahoo will ignore you. from then on.
I list in some myself but I do think it makes a difference if the directory itself relates to your site or if they have categories that fit you...I am listed in a number of green directories and do get visits from them.....Do avoid directories that have no structure and are just pages of sites listed as that can do as Peter says....Many of these small time directories are nothing sites webmasters made and use to create one way links for their clients...They offer you a link exchange...You put their client on your pages and that gives them a one way link...You are placed on some obscure directory that in most cases has no Page Rank at all and is not promoted in any way to the masses.