i lost PR...?

so, how exactly does one manage to lose PR?
alright, it ain't exactly a nice blog, and it has only 4 posts so far. yet i had managed to get it up to PR 1.

today i checked and it was PR 0....so how exactly does one lose PR??

3 Reasons that I know for why websites lose their page rank:

1)The backlinks that were looking to you removed their link

2)Your site has too many outbound links (you are linking to too many other sites, so you lose the link power)

3)A few websites that you are linking to have become banned, and it's damaging your site's rep due to the linking to their site.

There's other reasons as well, but this is pretty much the main reasons I've seen with my own sites and others.

ok...2 and 3 are pretty much out....
i guess it is reason #1 then

Not adding new content can cause you to lose PR as well.

that makes sense too....i never add anything there lol

SEO Methods used also affect the PR.If most of the Backlinks are from Viagra spammed pages, then you dont have much chances to hold PR