"Sending someone a direct link to your post results in an invalid upvote."

Is that true? When I share a story that I find interesting I send the direct link on identi.ca, twitter, and/or irc, and when I am the one who sumbitted the link I can see the upvote of people telling me that they have just upvoted. Has it always been a lucky coincidence? I can't think so.

Anyway, I think the only sure and valid way to get on the front page is to submit your (or others) stories only when you really think they are of interest for this particular community. This is what I do and it naturally works most of the time.