There are some who say you needn't bother having comments on articles at all, nothing constructive will come of it.

I am not a believer in that, it sounds very Science 1.0, but a paper in The Journal of Computer-Mediated Communication found that though only 12 percent of the American public gets its science news from mainstream media and magazines, comments held extraordinary sway among those readers.  Popular Science has declared that they have shut off comments on articles - permanently. And we've often debated their benefit here.

If most comments are rubbish, what does that mean for understanding of science that they hold so much power? 

That's a philosophical question for another time, but if you find your comments being ignored, there may be a good reason. I want to light a candle rather than curse your darkness, so this Top 5 list of why people don't reply to you is not constructed of bits like "you are a troll" or "you just insult people" (though having nothing constructive to say will also get you ignored or marked as spam), but is instead warning signs that people think you are wasting their time.

Without further ado, here is the first of the five, in no particular order: Occam's Razor.