In my test system, I have very few posts but several tags.
The built in linear tag cloud worked just fine. But when I added the log tag cloud, it doesn't appear.
I had them both installed at one point. I had hoped they were colliding somehow. But after removing the linear cloud, not tag cloud at all.
The log file does not show any errors.
I've kept the default values for the plugin.
I have a total of 8 popular tags, 5 tags used 2 times and 3 tags used once.
What might I be overlooking?