Passing parameters from one page to another - but not viewed in URL

[Gabriella]

Hi,

I have a website with ~20 ASP pages.
I need to send 2 parameters from one page to another (throughout ALL
pages in the website).
Currently I am sending them in the URL, through <a
href="page.asp?param1=x&param2=y>
but it's not good because it is viewed in the URL.
The important thing is that - I still want the current page's URL
viewed (very important requirement for me), also with other params -
but explicitly NOT with param1 and param2.

I don't know if the best solution for this problem is client-side or
server-side.

I thought of 2 server-side ASP based possibilities of solving this
issue:
1. Use the Session object with Session("param1") & Session("param2") -
but I've been told that if I have lots of users connected the Session
object would hurt my performance.
Moreover, when Session expires, things start to behave bad...
2. Use a server-side cookie to write/read these parameters whenever
needed - but again, it might hurt performance, as well as - what will
happen when the user blocks cookies?

Is there a better solution (client-side or server-side) for passing
global per-user paramters from one page to another?

Thanks,
Gabi.