Postica -- sticky notes you can upload to

For sometime I've been looking for an app that allows me to drag a file or photo or anything to a friends account from my computer, a sort of instant messaging for files. This would essentially allow me to use a much quicker and more convenient means of emailing stuff to friends/colleagues.
Tasque shows something like this in its promotional video but the version put now doesn't seem to include this (at least, if it is there, it's very well hidden).
Postica comes reasonably close with its sticky notes that you can attach files or photos or whatever to.
However, you still have to type in the recipient's address.
Incidentally, as part of my tests on this I send myself (another address) a note with a photo. However, 10 minutes later it still hasn't arrived. I wonder where it went.
In any event, assuming this non-arrival is just a glitch, this does look very promising.

Edit: Just sent again and this time arrived within 1 minute so it works.
Not bad but, in reality, not a whole lot more convenient than email given that you need to add the recipients address and then it's received just as a normal email with an attachment.

Edit (5-07-08):
A few more tests showed me the following about Postica:
i) Max file size for upload is 5 MB (apparently can only upload 1 file per note -- also no info on whether there is a limit on total size of all files on notes for each user, although it could well be unlimited as it is in Gmail)
ii) Sent notes (with attachments) appear in receivers Postica board with option to accept or reject (so no need to go to email)
iii) When you share a note, receivers address will appear in drop-down list

Really starting to like this!