dvduval - 11:42 pm on Aug 8, 2010 (gmt 0)
It's really easy to underestimate how much work is involved, and end up with loads of gaps.
This depends on the scope of your goals. If your goal is to make a "directory of everything" this is obviously an unachievable goal.
However, if you start with something like a town or city directory, it is very easy to get some useful categories up and running on the site within a few days or less. The same thing would apple to creating a niche directory.
If you are going to attempt to allow the submission of just about any link, you need to contemplate how you can introduce some limiting factors. Here are a couple of examples:
1. Increase the amount of work required to submit a listing, so that each and every listing will be created by someone who put a lot of thought behind the listing. Just getting the title, description and url is insuffient!
2. Create a system or triage that only promotes the best content to the top (ex. digg). For example, maybe the content will not be indexable by google until certain criteria are met (votes, comments, other popularity or quality measures).