And when you say "enterprise", think also of small and medium businesses. There are many advantages to webmail, but I keep running into smalls and mediums who

And when you say "enterprise", think also of small and medium businesses. There are many advantages to webmail, but I keep running into smalls and mediums who use shared hosting for email (IMAP and (shudder) POP3), but can't truly leverage "Horde" or other open source webmails. Their options are Outlook if they have enough licenses ($$), or Thunderbird if they don't. Yes, many move to Google's infrastructure if they can, but not everyone is able to or wants to. Thunderbird is one of the remaining alternatives.