You might be wondering why your backlinks suddenly drop after you check it using backlink checker tools like those simple tool provided by Yahoo Site Explorer (which you can use by typing link:http://yoururl.com). This is not a cause of any penalty nor banning thing but its more on the other website. Here are some of the possibilities that might be the cause of decrease in backlinks:
- Google removes the backlink value when the source site doesn’t exist. This is what the following video of Matt Cutt’s explained about Google’s treatment of Geocities, AOL member pages and other site that vanished in the WWW.
- If the source of your backlinks is from blog commenting, then the owner might have implemented something on its comment section and / or remove old comments. The owner might have implemented NOFOLLOW from previous DOFOLLOW settings.
- Search Engines change in algorithm sometimes includes a clean-up of links giving no value to some links nor discarding it from their index.
Remember, there’s no permanent in this world and backlinks are not excluded from this saying.