A thread from surfdude (Vaughn of the famous One-Pagers) has a thread at SEOChat on the value of link data fomr the search engines and the reliability of the numbers therein. He notes that as you drill down to the end of the listing results, the number of results reported by the search engines changes (at Google, Yahoo! and MSN). In the thread, several members, myself included, have provided the data from our own sites in an attempt to identify a pattern. On is not apparent, but some trends are worth noting.

It appears that Yahoo! is always providing the best and most accurate link data, confirming the long-held belief from SEOs like myself. Yahoo! not only reports the most accurate numbers, but stays the most stable in their reports as you surf to the end of the listings. This is accomplished by changing the variable at the end of Yahoo!'s links search URL to 999 (indicating it should start by listing the 999th result).

It's worth trying this at your own sites to see just how many links Yahoo! really knows about. If you have thousands of links from the same domain or from very low quality domains, it appears that your link list will be seriously shortened when paging to the end of the link results. This could possibly serve as a metric for measuring average link quality if enough data is compiled on it.