Si Ballenger wrote:
Don't put clickable links to it in a pubically accessable web
page.
Not reliable. Google Toolbar (for just one) is a backchannel that
feeds the URLs of "hidden" web sites back to Google, where they then
get spidered.
You also have no control over other people linking to your site.
If you want to "avoid indexing", then just use robots.txt (Maybe your
site isn't released yet).
If you want to keep your content hidden, then disallow anyone and
everyone from accessing it (by web server config, such as .htacccess).
Then specifically _allow_ content to be visible to a small set of
permitted users, such as by password access.
There is no practical way to identify "a spider" as distinct from "a
user". So any attempt to make content generally available and
_disallow_ spiders is always doomed to be unreliable and susceptible to
some level of leakage.