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check out the help page here: http://www.seomoz.org/help/open-site-explorer-faq is your site new? that could be a factor... OSE isn't going to show EVERY link - and keep in mind, if you have about 150 links showing in WMT, it's possible that those are from less than 50 unique domains... but even if not, if none of the sites linking to you are sites that get crawled by OSE, then your site won't show any link data. (so if you're not linked to by one of the URLs it uses, which is only about 25% of the URLs in Google's index, you won't show link data) also, I noticed that you're don't have a 301 in place for your non-www version of your URL - you need to get that in place, it's important to avoid them being seen as separate sites.