traffic checkers?

[real]

Maybe title is not the best one.

What I am asking is this:

Can a host or admin redirect some traffic coming to some internal pages
of a site from to time in a hard/imossible to detect way?

Is it possible to check if some traffic goes elsewhere?

For example alexa can show a list of related sites.. Something similar would be good. For example a paid version of alexa which shows more detail would be great.

[mad4]

You are asking if a host can siphon a few percent of your traffic and divert it to other sites?

I am sure they could but whether they would is another matter. What makes you suspect this?