Google Tool Bar
Google Tool Bar is very useful at getting an accurate PageRank for any site while you are visiting the site. By having accurate, real time information about PageRank eliminates having to switch tabs or windows in order to see the PageRank of a site. Not only does Google’s Tool Bar provide page rank information, there are a lot of additional SEO related features that can be added from third party sources.
Robot.txt files can really benefit your site’s optimization. Being able to tell a search engine that they should and shouldn’t be searching allows you more control over what keywords a bot may find. If you are using a CMS you would want the bots to leave your admin directory alone since that is something that a limited number of people have access to, and shouldn’t be searched. Robot.txt Checker is designed to make for sure that if you have exceptions like so in your robot.txt, that those exceptions don’t have any issues which may allow a bot to search those areas.