Login
Yep, you need to do that :)
auto first post, and comment
when you join Jaiku an automatic post using the "V-fingers" icon with the Text "Joined Jaiku" is posted to your stream.
At this point you can click the "add Comment" link and add a comment to your post.
Comments are limited to 2000 characters per comment, and you can use most of MarkDown's syntax
second post
To create a new Jaiku post, click on the "Home" link and start typing. Note you have 140 characters for your message, but if you need more you can alsways add a comment.
You can add an icon to your post from the available selection.
What's next?
Once you have tried that you can check out the #test channel (note that entering a hash character makes a link to that channel in both jaiku's and comments). And experiment there to your hearts content
Next you might want to check out channels