Usefulness of site and host fields?

[Markus Jelsma]

Hi devs,

What exactly is the usefulness of this piece of code in the index-basic 
plugin?

68      if (host != null) {
69      doc.add("host", host);
70      doc.add("site", host);
71      }

I believe we can remove the site field. It'll decrease large sets and Solr 
implementation can still use if (if they must) via copyField or in Nutch' Solr 
mapping.

Thoughts? Is there some reason i am missing here?

Cheers,