As some of you probably know, Google provides an "on-line office" - AJAX-based web application, which allows you to edit formatted text and spreadsheets on-line, storing them on Google's servers. There are some extra features, including change tracking, sharing of the same document with other Google users etc.

I tried to edit a very simple spreadsheet today. Although the interface is quite slick and not dissimilar from, say, Excel, it is far from perfect. Some quite straightforward operations are missing (Copy sheet, for instance). It is also very slow for many operations - adding rows/columns, changing format of cells and so on.

Maybe it's much more convenient to download the document first, edit it locally and then upload it back. However, being able to edit the document on the web contains 90% of attraction of the new service for me.