Bashiok has promised to bring an end to the eating of posts on Battle.net. Whenever a Battle.net member takes a long time to write a post, the content will disappear when the poster hit “Submit”, which is primarily a frustration to fans that write long posts. This was apparently never supposed to happen, but when the forums were upgraded, we never got the safety feature in the forums that would save the post when asked to log in.
Until then I highly recommend writing any long posts in a text editor and then copying and pasting them into a post. Sorry again.