Search engines will determine your page content by analyzing the words on the page. Although there is no hard and fast rule on how long your content should be, it is recommended that you have at least 400 words per page.
It you have too little content on your page, search engines will not be able to idenitify the content and you may have trouble ranking highly.
If you have too much content on your page, you may be penalised for long loading times and having too many links. In this case, you should split your page into a number of sub-pages, if appropriate.
Optimal Word Count & Web Page Copy Length - seobook.com What is the optimum number of words, per page? - Google Webmaster Forums