Question about realtor listings

I found a house on a realtor site, they listed the address. I went to the county tax assesment website to find the appraised value of the home and it listed the owner. Can I contact the owner directly instead of going through the agent?

if you are on full mls, not just a site attached to mls, it should say what kind of listing it is. i.e. exclusive agency (ea), exclusive right to sell (er) or limited or some hybrid thereof. if you are a licensee and it is listed you cannot directly approach the seller, if you are jqpublic you can, but regardless they may be obligated by contract to inform and negotiate through, or at the very least compensate their agent.

Sure you can. Depending on the listing agreement you might be able to negotiate some extras if you know what your doing.