dtm is "partially" correct.
Yahoo shows better inbound links than Google's site and Google's webmaster tools solution offers more accurate inbound link info as well, however they're all mis-leading and inaccurate. This reality changes over time as both Yahoo and Google work on their algorithms.
I maintain the SEO initiatives for a plethora of web sites. In just one example, Yahoo shows over 350 inbound links - google.com shows none, and Google Webmaster tools shows 65. Note too that recently Googles Webmaster tools system has been very unstable - having intermittent difficulty processing site verification requests, generating incorrect information regarding sitemap.xml files for short periods of time, ect. So I am guessing that their link: feature is also currently less than accurate.
The Yahoo results include in their results about 50 of the site's own pages, implying that pages within that very site are providing links into itself. The whole notion of the link:www.mysitewhatever.com feature is supposed to show how many other sites link back to my site, so those 50 listed pages are not supposed to be there.
This happens because their software is far from perfect.
Nevertheless, Yahoo's results tend to be more accurate than Google's for the most part. This wasn't always the case.
As for Google's results, I've found that in recent months, they're really only showing links back from sites that for the most part are, themselves, ranked sites. Yet refer to my note above about the intermittent issues Google's been having...
It's not always about how many sites link back either. The higher the rank of a site that links back, the more weight that one link carries. So a link back to your site from cnn.com is going to carry more weight than a link back from somegenericsite.com
In any case, just keep doing what you are doing - it's all always about time and energy. Apply enough energy over a long enough period of time, and the results will follow.