You can format your messages using fonts, colors, highlights and so on, and you can send attachments and links as well. And, as mentioned before, you can embed other kinds of content directly in the wave -- by using Google Wave gadgets.
Gadgets and robots
If Google Wave ever takes off, the gadgets will be key to its success, because they can potentially integrate Google Wave with other existing services on the Web. For example, there is a voting gadget that lets people vote Yes, No or Maybe. There are also gadgets for conferencing, video-chatting, playing games, getting weather forecasts and more.
At this point, though, there aren't many gadgets available. And finding and installing them is problematic. When you click the gadget icon that appears when you create a message in a wave, all you get is a dialog box asking you to type in a URL. It doesn't let you browse through a gadget library or preview gadgets. So you'll have to find each gadget on your own, copy its URL, and then paste it into the box.
In the existing Google Wave preview, there is another way to add a gadget -- by viewing a Google-supplied wave that has a little more than half a dozen gadgets. But there are more gadgets being created by third-party developers, and for now, there's no central way to find them the way there is to find, say, add-ons for Firefox.
In addition to gadgets, you can also add "robots," which can participate in waves almost as if they were human participants. You add a robot to your contacts list, and then when you want it to perform an action, you add it as a participant to your wave, in the same way you add a human participant.
For example, there's a robot called "Bloggy" that you can use to publish a wave to your Blogger blog. Another robot performs an automatic search of the Guardian newspaper and displays the results it finds, including headlines and links to the articles. To use it, you add firstname.lastname@example.org to your contacts, invite it to a wave, and then add the text "Search term ?guardian" to a message in the wave (using the words you want to search for instead of search term), and it will perform the search and display the results.
Public or private?
Your waves can be public or private. Only people you've invited to a private wave can view it or participate in it, but anyone can view or participate in a public wave.
You need to be extremely careful about what waves you make public. And during beta testing, I found a serious security hole -- one of my private waves was turned into a public wave without my knowledge. I had added the Bloggy gadget to a wave, but because the gadget didn't ask for any log-in or blog information, I assumed that the wave was not published as a blog. It wasn't -- but the gadget made the wave public without telling me. I only learned that the wave had been made public when someone I didn't know joined it and warned me that the wave had gone public.
Clearly, this is something that needs to be fixed. If gadgets or robots can make a private wave public without your knowledge, Google Wave will be one of the biggest security holes ever devised.
So why would you use it?
How useful will Google Wave really be at work? Imagine, for example, that a geographically dispersed group in an organization needs to decide when and in what area of what city to meet.
The group starts a wave discussing the meeting time, place and agenda. A gadget links to a group calendaring application so that the members of the group can view one another's schedules and find potential times to meet. People make a variety of suggestions and use a polling application to take a vote deciding on the time of the meeting.