Very soon I wanted to start a public wave (topic) myself. I searched google and found nothing and I searched inside GoogleWave and found this (sorry that I don’t know who this article should be attributed to):

How To Find Public Waves

you search group:public@a.gwave.com. To find only English waves search lang:en. Add tags to refine your search: tag:wavedev for example. (Add your friends to this wave so they can see these directions.). See step 4 below for a list of tags you can search. You can remove blogger posts with -with:blog-wave@appspot.com.

You can also search for “with:public” to read all the WAAVVVESS.

If you are just getting started and need help, try searching group:wavehelp@googlegroups.com

How To Make Public Waves

1. add public@a.gwave.com (not googlewave!) to your contacts in the lower left, using the (+) next to “Manage contacts”.

It will say the account doesn’t exist, PRESS the Enter Key to add anyway! (not click the button)

2. Add this public contact to a wave you want to have be made public

3. A Yellow/Beige bar will appear saying “Everyone has access to this wave.” This means the wave is public.

4. None of the above work for some users due to yet another bug. A good workaround is to add easypublic@appspot.com instead.