Yup, I believe that's what they're doing. The trouble with this approach is that IMAP servers are painfully slow for server searches. Very few of them build an

Yup, I believe that's what they're doing. The trouble with this approach is that IMAP servers are painfully slow for server searches. Very few of them build an index. Interestingly, doing searches against Gmail's IMAP is also dog-slow :-(