I don't think you can really have 'too much' content on a site. I suppose if you're very busy with writing new articles then you could have lots of content and it might become difficult for a surfer to navigate. If that is the case then have lots of categories or sub-categories and have a navigation bar on the top or side-bar of each page so you your surfer can easily find a relevant topic.
For instance, if you're talking about animals then you may wish to categorize your pages by geography ( eg. African animals, Australian animals, etc. ). Otherwise you could have thousands and thousands of pages if you talk about 1 animal per page and it would be hard for a surfer to navigate.
For SEO try and cross-link relevant articles ( eg on your african bird page contrast these birds to australian birds and put a link to your Australian bird category page ). Always try and create a chain of natural flowing links from your main index page to your deeper pages so that search engines can crawl and index all your pages.
Place a search box on your site so that users can find specific topics quickly. If you don't want to program a search box then sign-up for Google Adsense and copy and paste the code which they provide for placing a search box on your website. In addition to making your site searchable to visitors you might even earn some extra cash from Adsense.
By Kyle Ware