I'm wondering who decides that a post is off topic.
I wrote my first blog entry in a long time today was confused when it didn't show up on the main site.
After trying to figure out if I had not published it properly or set some specifc property, I eventualy noticed the two links for On Topic Only and All Posts.
I don't need the entry to show up on the main page, but it doesn't seem to be further off target than some of the other things that are in the main feed.
Edit : I think I figured it out, use the "Asp.Net" tag :P