Yeah just 2 days ago I had nearly 700 Backlinks. I checked today and I have 4 Links. And they are all from pages on my Blog.

What is this ?? Has anyone else ever have this happened to them ?

Just about everybody at some time or another.

Check your links in Yahoo use the operator linkdomain:domain name
Google doesnot show all the links. There may be many reasons for a sudden fall in the no. of backlinks. Check your backlinks using a backlink checker and find out from where you have lost links.

Google does not show the exact number of backlinks of a certain site, but still you may try some backlink checker!

For me Yahoo site explorer is good for finding new backlinks, I sometimes find some very unusual sites linking to my sites.
Try it, they list some backlinks you wouldn't even think they could be counted as a backlinks.. lol

There are different ways of searching so there are different kinds of results.

A friend of mine also suffered the same. I think Google is now strict when it comes to counting backlinks of a site. I just read an article that google will not count backlinks from directories anymore.