"GMail searches must search a genuinely real-time index of your e-mails. An e-mail must be searchable the instant it's created." That's not a significant differ

"GMail searches must search a genuinely real-time index of your e-mails. An e-mail must be searchable the instant it's created." That's not a significant difference in terms of searching. The index segmentation is not likely to have a significant impact for most queries, and the segments are likely combined often enough for it not to be a problem. It is real difference is that the infrastructure to support searching your one little inbox index just isn't there. It's probably not constantly loaded into RAM. It does cache queries though, try, "red" then "green" then "red". Another difference is that is shows well more than 10 results.