Rallypoint joins Writely, JotSpot Live, Zoho Writer and others (I lump services like Writeboard and the yet-to-be-launched Chalk in this category as well – a wysiwyg wiki and a sharable online version of word are effectively synonyms).
Rallypoint has some great features, but is not as robust as Writely yet. The beta account is allowed only 2 MB of storage. And while they allow pasting from word (?), they do not have an import or export feature.. Rallypoint does have wonderful image and media uploading (with a built in player), and rich sharing/permission features.
For more information on Rallypoint, check out Brian Benzinger‘s post on the product.