(We've been doing some things like this in network management rather than WWW,
and we're using Scheme and other compact languages rather than TCL.)
I think it's important to make a very clear distinction between
scripts which are to run in (or alongside) the user's browser or in
the user's computer from those scripts which are to run in servers.
The security and resource consumption concerns are different.
What we had (have) trouble with is this: Management of the scripts
that we've launched to servers. The trouble is that they can migrate
away or that we (or our machines) somehow forget about their
existance. Sometimes we want to kill-off a worm that did unexpected
bad things. Overall, it seems a bad idea to have the ability to
launch a potentially infinite-lived worm out onto the net. (Now, where
*did* I put my copy of Shockwave Rider?)
--karl--