> ..or taking forever sync. This is really amazing.
I don't think this solves the problem of taking forever to sync. Nothing has changed there. You are still bound by the same data retrieval and network latencies to get the file stored in a datacenter somewhere to you. That one is a harder problem to crack because it needs a lot of infra investment in expanding your content delivery footprint and replace SSD's with something much faster, like flash.
This solves an important aspect of the sync problem -- the ability to selectively sync individual files without having to sync the whole directory that it is part of (or even to have to know what the directory is in advance).
Dropbox has actually had Selective Sync for years. The whole part about the metadata being cached locally and a seamless experience at file system level is new though.
I don't think this solves the problem of taking forever to sync. Nothing has changed there. You are still bound by the same data retrieval and network latencies to get the file stored in a datacenter somewhere to you. That one is a harder problem to crack because it needs a lot of infra investment in expanding your content delivery footprint and replace SSD's with something much faster, like flash.