[quote user="Mottel"]
I've found that Pegasus can have concurrent IMAP connections open to two servers, and copy emails from, say, a Yahoo mail acct to a Gmail account by copying them from one IMAP folder to the other in Pegasus.
[...]
I'd like to know: is that date going directly from remote server a to remote server b, or is it going via my computer, so that (if the latter is true) I'm really downloading and then uploading each item?
[/quote]

The latter; yes.

I am an old hand at using Pegasus (formerly as a POP client), but I had a long hiatus from it until now, first while I had a Mac and later, when it died, while I was using web-based mail (several accounts with different providers). I have now taken up using Pegasus again, this time mainly as an IMAP client to (hopefully) control all my webmail from one client. I've found that Pegasus can have concurrent IMAP connections open to two servers, and copy emails from, say, a Yahoo mail acct to a Gmail account by copying them from one IMAP folder to the other in Pegasus. Now, before I perform a really large-scale operation of that nature, I'd like to know: is that date going directly from remote server a to remote server b, or is it going via my computer, so that (if the latter is true) I'm really downloading and then uploading each item?