Hypocrisy literally means criticism of others, by a standard one does not apply to oneself. It is hypocritical to use a double standard which strictly applies a rule to one group of people, while exempting or excusing another group.
For example: Suppose a politician criticizes an opponent for "catering to special interests," rather than saying and doing things which benefit every constituent. If this politician is also "in the pocket" of special interests, it would be hypocritical to critique an opponent for doing the same.
Yet charges of hypocrisy are not so often directed against practices as against people. It is not that the critic really opposes "catering to special interests", but that they just want that particular politician to be silenced or removed from office.
- A mere accusation of hypocrisy can halt a debate by silencing the accused, forcing him off-topic to defend himself against the tangential charge of hypocrisy. This is how and why so many talking-head shows quickly degenerate into everyone accusing everyone else of hypocrisy, with nothing of substance actually discussed.
- The treatment by the nation's news gatekeepers and liberal groups of racist or bigoted behavior varies wildly depending on whether the presumed guilty party is a Republican or a Democrat (or conservative or a liberal). 
- Some conservatives have pointed to Gore's use of a private jet while spreading the message about the dangers of global warming.
Hypocrisy is a common fault in many individuals of many affiliations. Ironically, many people are quick to accuse other affiliations of hypocrisy, while refusing to consider the idea that they might be so themselves.