There are two domains that will work for use as article directory sites. My experience developing an article directory is less than positive. I used a article marketing plugin available atg clickbank but within a week plugin errors boosted the size of the MYsql database to a hundred megabytes. I think the concept is worth revisiting. Ideally there is a similar auto blog plugin where content moderation actions are accepted. After running myh article directory I abandoned it because 10000 tags, and 5000 categories could not be managed even when moderating and rewreitall day. The product is a plugin and a article directory wordpress theme. Other IM ideas you might consider are a TE oer Fiverr clone.