All the recent discussions on backups and the peer to peer question has suddenly become a bit more relevant to me as I'm playing with Calibre for keeping my E-Books.

I installed Calibre on my desktop machine, it's improved quite a bit since I last played with it and it now fits my requirements rather better than before. So I've imported quite a few E-Books into it and have started sorting them out a bit.

However I then realised that E-Books in particular need to be able to be carried around with me, so I want them on my laptop as well as on my desktop machine - synchronisation!

Initially it feels as if there's a lot of choice but in reality there isn't if you filter with the following basic requirements:-

Must work across the 'net in some way or other, just file synchronisation doesn't really do what one wants. It needs to work when not connected as well though so a remote FS is no good.

Should update automatically, preferably in 'real time'.

Would like it to synchronise existing directories, not require things to be synchronised to be put in a special place.

Looking at the Wikipedia list there's only two or three satisfy the first two requirements and adding the third seems to mean nothing does what I want. I guess Conduit might do it but it seems to be dead which is a pity. Owncloud is possibly the least worst and has the advantage (for me) that I have a Owncloud server running already. It expects you to put files in a special place though.