You choose the same way you would at the field or FTF, but you have fewer clues to go with. You use your bull**** senses to evaluate what you read. Does what the guy says make sense? Do others agree? Has he explained it carefully, or wrote off a one-liner? Does it really answer the question you asked, or is he just showing off his knowledge? Personally, I take everything here with a grain of salt. If I get a great idea here (which I do a lot), I test it out myself, and if it works, I adopt it.