I've found that writers who haven't made money yet from their writing activities are often sqeamish in claiming their losses --- the excess of their costs over their income --- against other employment income or self-employment or investment income. I write about this in my tax book for writers, and discuss some tax disputes that have actually gone to court where the IRS was calling the writing activity a hobby, while the writer was claiming it was a business.
In that vein --- although it doesn't involve a writer --- I found the case of John and Esther Chow interesting. You can read it at
http://www.ustaxcourt.gov/InOpTodays/.... It's about Esther Chow and her argument that she was a professional gambler. She had gambled for awhile and was claiming gambling losses from her gambling on her income tax return. The IRS said her gambling was a hobby.
Esther Chow won the argument before the Tax Court.