Clarebear
I agree with you entirely
It is best to approach this with caution

How does the old saying go ? "
Beware of Trojans bearing gifts"

I'd love a big mailbox,I want a reduction in Spam.

I do not want to have 1000s of messages cluttering up my email box

unless it's personal and a timed auto delete which can be set? Otherwise You may see the server will go down regularly when it gets to Capacity?(depending on take up?) I wonder If they have done their sums on that?
And can it be sorted easily

(and Of course a Report/block abusive mail controls (very important)
As for the AD's I think they'll be along the lines of what Hugh was running on this site
Does anyone remember
Altavistas attempt at a free Email service? and How long before it became a "Pay" service? and C) It collapsed shortly afterwards with about a months notice to A/C holders

They had plans to become an ISP but they changed their minds for some reason

I used to visit the
www.altavista.com site daily but it is poor value after this project that went wrong

Another search engine
www.northernlight.com used to be a very good site (top 10) now look at it

I'm surprised it is still in existence due to the policy decisions that were taken
