WebSite Auditor scans pages for code errors, duplicate content and other structure-related issues they may have. Other than that, there is this on-page optimization module, which allows determining the ideal keyword placement and researches page elements that can be optimized. In WebSite Auditor you can also analyze competitor’s pages to compare of to improve own on-page strategy. There are actually more features, I just won’t be listing all of them here. But this is the best solution with regard to on-page optimization I found so far.
This broken-link checker makes it easy for a publisher or editor to make corrections before a page is live. Think about a site like Wikipedia, for example. The Wikipedia page for the term "marketing" contains a whopping 711 links. Not only was Check My Links able to detect this number in a matter of seconds, but it also found (and highlighted) seven broken links.