Hey jkomp, To develop you could make it a forum/portal site giving advice on how to gain pagerank and therefore improve on SEO; either that or make the site a directory of companies that could perform this service. Either way, you'll be building a community of users and therefore making the site more attractive to potential buyers. Mike.
I see a good future for a well-developed Gainrank.com. Like it was said before, a good descriptive name, and on top of that a .com domain as well. I would suggest to start off with a lot of articles on what ranking is, why it is important, how to gain it, etc. Secondly offer numerous free SEO services, especially site submission and ranking checks (there are many free php scripts to help you on your way). Thirdly, offer webmasters tools, software, cross-linking facilities and more, which can be adventageous to them. This will help you to start building a community. Then set up a forum where visitors can communicate and share ideas and discuss problems, etc. Once you have a strong repeat visitor and large community rate I would sy your site could easily be sold for an amount exceeding $10 000.
Its an improvement. Remember what you need to focus on when attempting to sell your site: Generate good visits, especially return visits and improve your income you generate on the site. Sent you a PM with some suggestions.