This was quite an interesting question and the reason being is because pretty much every search engine out there will allow you to add your url to them.Sometimes you simply add your site or blog.
Sometimes it is a paid inclusion. Photo courtesyof a great little blog.
Sometimes it is through a sitemap.
Etc, etc.
The thing about Dogpile is that you can't add your url to them at all. Period.
Why not?
Dogpile gets it's listings from the big boys like Google and Yahoo and Msn etc.
So now you know that you can't add your url conventionally but if you are laid out and seo friendly then you will get listed with them.
I hope they hurry up and add me soon ;) Hint, hint to Dogpile;)
Best
