I would like to know if there is a mail client that just "reads" and sends emails without having to download them on the hard drive, due to limited disk space. The advantage over using a web mail interface is that the mail functions centralised for all accounts. Thanks for your contribution.
You can tell Thunderbird to use IMAP and not store attachments bigger than a given size and not keep too many emails on your computer.
I guess you cannot download no emails since they have to be displayed somehow, but this will minimize memory usage.