Your pinterest link is borked.
Design looks pretty clean.
I would bump the font size for legibility.
I personally would avoid having tags in a tag cloud having larger font sizes than my main content, it is somewhat distracting. I think I would lean towards surfacing "related content" next to each post instead for discovery.
I would change the latest entries to take up both middle and right column, and, most importantly, add a single paragraph summary/teaser from each post next to each title/image. Right now the title and image gives me very little idea of what the post is about.
The main image looks very blurry/over-compressed, I would definitely suggest replacing it with a cleaned-up version.
The thumbnails also have inconsistent levels of quality, some look clean, some look over-compressed.
If you are linking to pinterest and facebook, I would suggest also creating a list page on stumbleupon, might be helpful. Here's an example: http://www.stumbleupon.com/lists/840022691085624002