Alberto wrote:

If I use an IMAP account I can access to my email also via web (in
most cases) and if I delete some msg from web these go to trash
folder.

You can't access an IMAP account via a web browser. You can access a
_mailbox_ via a web browser that an IMAP server also references, however.
In thiis case, the web browser's access methods allow working with a trash
folder. The IMAP protocols, however, do not implement such a folder.

If IMAP protocol don't use a trash folder concept, does it use a
"spam" folder as Outlook ?

The IMAP protocols don't, per se, but Outlook adds one (that's local to
Outlook's IMAP PST) and can perform junk processing on the IMAP account's
Inbox. If a message gets moved to the Junk E-mail folder you see in the
IMAP PST, it will be on Outlok only, I believe. I don't think Outlook will
create a Junk E-mail folder that can be seen on the server side. I can't
test on Outlook 2007, right now, but that's the way Outlook 2003 handles it.
I know, however, there were significant changes in Outlook 2007's IMAP
handling, so perhaps it has been changed.
--
Brian Tillman [MVP-Outlook]