A word on hoaxes, scams and urban legends:
Microsoft will not call you to tell you that you have a problem with your computer. No need to give them your personal information.
No one needs you to funnel money for them from Nigeria. No need to give them your personal information.
Missing persons alerts may be valid if they contain in depth information on what the person was wearing, where they were last seen, and a complete description. A lack of information may be a sign that it's not valid.
Changing the words of national anthems, removing well known lyrics by US President Obama/Prime Minister Harper/Famous World Leader is not something that can be done overnight. Well, that was tried in Canada. There was a short lived movement about changing them by the government, followed by a swift backlash, and nothing came of it. Despite having tremendous power, there are still a lot of checks and balances that world leaders have to deal with.
Changing of government regulations and laws fall into the same category as the one above. Major legislation doesn't happen in the blink of an eye. It can take years, and the press loves to milk every minute of it when they find something juicy.
Conspiracy theories that tell the 'real truth', but the government will never let you know about it. While world leaders may have a tight rein on their immediate subordinates, and their subordinates have a tight leash on their own subordinates, etc., etc., No one is squeal proof. Bill Clinton as president held great power. But eventually the facts concerning Monica Lewinsky came to light. In Canada there was a scandal involving expenditures by senators. Three were kicked out, and they were members of the governing party. The fact is, no one can keep a lid on everything 100% of the time.
Ultimately, when in doubt, check it out. Check out a few sources. If a bunch of sources say the same thing, without the exact same wording, chances are it may be true. But if several sources keep saying that it's not, don't spread the spam, and don't get taken.