Deadwood is the greatest show to come along since The Sopranos. A show that is for 17 and older. It realistically shows how things were back in the 1870's, during the gold rush. It's violence, language, sex, and racism which existed makes it so believable. As well as the drug use. The acting is incredible and the way creator David Milch captures every scene with realism especially the drug use speaking from experience is exceptional. Each episode can be watched over and over without growing tired of.
I agree with the synopsis above (if you haven't been using that word for more than 10 years, this show is not for you) is accurate. Moreover, I think that there are many adults out there who would be appalled by a lot of the situations in the show (the language being the first one that comes to mind).
That said, this is probably the BEST show I have ever seen. It has a depth and philisophicalness (I know that's not a real word) that is unparalleled. I was saddened by the end of the series, and I mourn the show often.
This is a fantastic show, incorporating true historical people into a semi-fictional show. Sure, there's a huge amount of violence, sex, drugs and language (to a laughable extent, in the case of language), but it doesn't detract from the amazing show in any way.
Amazing and Good for mature 16-17 year old's but NOT for minors the violence includes sexual violence (rape) bloodshed the cursing would make HAPPY GILMORE blush low REAL strong sex scenes and no strong drunkenness but the realism of the show will have product placement