I go to Google's Webmaster tools, and check my external links. It shows 830 external links. Every other backlink checker shows only 24. Am I doing something wrong or reading the results incorrectly? Also, when checking these 24 links, they are all irrelevant and carry no PR. My yahoo links are much more numerous and show many more relevant links with PR.
First, you did not mention how many backlinks were being reported in Yahoo Site Explorer. How did that compare with GWT reporting? Every SE backlink list is reported differently. Normal Google web search for backlinks only show a representative sampling. This sampling can, and usually is very low. Not all links get reported here. The Webmaster Tools backlinks are a little more accurate, but I am not clear on whether they are all being reported or if the links are of any worth. Still this is pretty good representation of what real links you do have out there, regardless of the value that Google will actually apply to that link. Yahoo Site Explorer reports almost every link they can find. That includes links on garbage pages that Google would not even consider, plus the reporting of Nofollow links as well. Most people get a real ego boost when they start bragging about how many thousands of links they have on Yahoo. Forum links are duplicitous for there is no effort in thinning out multiple Urls that point to the same page (ie One post in one thread could yield several page Urls and Yahoo considers them all different).