Link harvester is a free (and open source) link analysis tool which helps you spider past the 1,000 search query limit by making it quick and easy to filter out sites that link to you multiple times.
Link Harvester grabs:
-the total number of unique linking domains
-unique linking C block IP addresses
-.edu, .ac.uk, & .gov backlinks
-total pages indexed
-links pointing at a page or site
the tool does not spider web pages because I wanted the tool to be the fastest one on the market. it uses the Yahoo! API so it complies with their TOS.
the tool is free and open source. you can try it out here:
http://www.linkhounds.com/link-harvester/
you can snag the source code here:
http://tools.seobook.com/link-harvester/
by seeing details like how many .edu and .gov backlinks they have and how many unique linking c blocks point at their site it can help you gain a good idea about how competitive a marketplace is.