The following is to clear things up for people trying to add their mod and or site to the topsites system and are finding it confusing!!
When you register @ ModDB.com you can list your mods or your sites!
To list a mod you must add the mod than go into your Control Panel than you select manage under Modifications. Once you have done this you select the mod you added. Again selecting manage select Get HTML and choose either the moddb or the new html icon recently added.
To list a site all you need to do is go into your Control Panel than you select Top sites at the bottom!
I hope this helps!
Basically do exactly what BW said. To list just a website, go into your Personal Control Panel right here: Moddb.com and do what it says
If you wish to add your mod, you must goto your Mods Control Panel!! and add it there, under the 'topmods' section!