Broken Link Checker
Quickly find out if you have any broken links on your Website so you can fix them.
Tools
Google Datacenter Search
See where you’re ranked for any given keyword across all of Google’s data centres with this great tool.
Pages Indexed In Search Engines
Find out how may pages you currently have indexed in Google and Yahoo.
Keyword Density Checker
Great tool to check the Keyword density of a Webpage so you can optimize it.
Link Popularity Checker
See how many backlinks the main search engines have you down for.
As a successful ecommerce retailer I can tell you that the techniques taught by NetSalesTrainer are what I have used to generate thousands of sales. It is a very comprehensive, easy to follow course that does not break the bank. 
If you are new to ecommerce it seems almost impossible to find all the information you need to get started all in one place, so I'm pleased I found NetSalesTrainer. From start to finish, I found the course easy to follow. Not only are there videos which I find much better than learning from a book but there's also lots of useful tools along the way.
Using NetSalesTrainer was easy. I found that to be able to watch videos of things being done made it much less of a chore when it came to replicating it on my site. Also, I was very pleased at being provided all the resources within each lesson. It meant I didn't have to spend too much time working out how to use them!