The life of a website should always be cyclical in nature.
The cycle consists of analysis, updates and promotion. If any part of the cycle is left to flounder the success of your website is in jeopardy.
Analysis involves:
Reviewing your website and your web stats
Conjuring up new ideas content, and features.
Updating involves:
Adding your new content, design, or modules to the site
Promotion involves:
Search engine optimization campaigns
An eNewsletter highlighting the launch of the site modifications