A DigitalPoint Forums thread reports that Yahoo Site Explorer has done a major update to their linkage data reports. Most webmasters are reporting huge drops in the number of links reported today versus the days before.
The linkage drops are reported as high as losing over 5,000 links. Others saw a drop of about 1,000 links and so on.
It is possible it is a temporary reporting glitch, but some are actually speculating that Yahoo is no longer showing links that are not counted, either nofollowed or simply not counted, in the linkage reports anymore. Right now, it is too soon to know for sure. But if anything changes or if more reports come in, I will do a follow up post.
Forum discussion at DigitalPoint Forums.
Update: Just wanted to add that we reported similar issues in March, where my link count then was 271,196 inlinks, but in October I had 216,880 inlinks, and now I have 247,183.
