The Vertical Measures team serves up a review of the Link Harvester link evaluation tool. "It allows deep database querying of the Yahoo! Search database via the Yahoo! API," the team says. "As far as we know, it is the only link tool on the market which specifically specializes in allowing you to easily and quickly query beyond the Yahoo 1,000 search result limit."
You plug in the domain of a competitor's Web site and get info on the number of unique domains that are linked to it, their IP addresses, as well as the breakdown of links that come from .gov, .edu, and other unique domain extensions. Armed with this information, you can find out which sites your competitors are snagging links from and submit your own link requests.
You can also figure out the strategy behind their link-building efforts. For example, the Vertical Measures team used the tool to check out a popular retail jeweler's site and found that they had thousands of back links--a number of which came from educational domains.
"That sounds strange at first, but we followed those links and discovered that the links were to schools specializing in jewelry design who referenced the retail jeweler's site as an example of a particular style of jewelry making," the team says.