Credibility Meter

When we pick up a Tabloid off the newspaper stand, we know we're reading rubbish. With blogs and wikis though, I feel like its easy to be tricked into believing what we read. Many people are jumping on the blogging bandwagon, including already established politicians and media personalities. When I read politically driven blogs with fancy looking charts and statistics, can I trust what I read? It seems credible, but who's checking to see if the information is correct?...Nobody! How about when I want to learn about the Roman god, Pluto. I go to Wikipedia. It's an encyclopedia right?....one that anyone can edit! Should I then cite it on my big Org Comm paper?...or is that just as credible as citing my friend Joe Shmoe?