How do you know if someone really is who they say they are? The internet makes this judgment task exceptionally hard. There are no faces. You don’t even know if the person you are talking to is a female or a cross dresser who hasn’t showered in six weeks.
First, you need a base of experience yourself. Bullshitters can be caught quickly when nothing they say fits reality. If you don’t know a thing about the subject at hand, you are flying blind. US investment banks had an easy time hawking complex and overpriced financial services to municipalities. Con artists know making marks feel smart is incredibly powerful.
Second, look at motivations. Does this person have something to sell you or some deal to do? If they have blatant commercial intent, set your credibility meter to 0. People will say and do anything to make money. But hey, we are in business. I have something to sell and so does everyone else I know. The key is do they have something to sell you.
Third, be able to test what you hear. If a claim is untestable or unprovable then your best off ignoring it. You can immediately throw out cult leaders and instead spend your time focusing on reality.
I’ve met many people through the web. Some are genuine, others are clearly liars. Most I’ll just never know who they really are. However, I don’t really care. In general, I judge people based on the usefulness of the information they provide. If a get-rich-quick blogger who never made a dime in their life writes something, and I make $10,000 off it, wonderful.
Because I have been running my business for a while I have some sense of the accuracy of an individual’s advice (rule number one.) If 90% of what someone says is in line with what you already know is true, its a good bet the remaining 10% is true.
Just starting out? Then you need to build up some first hand experience before going all on based off of what someone else says.