Ask HN: How to properly cite sources online?

Edit: Ahhh some websites appear to already do this, "Top laptops..." but I wonder if it's old laptops or new ones. Easier said than done, have to comb through the market... spoke too soon as per usual. Still, I don't really have any better ideas and there's something about sorting/collecting data. I'm looking to do something like a monthly laptop buying guide, not on current-new laptops but what you can buy used that's actually a good laptop. My sources would be from eBay (actual products/pricing), and forums that discuss known problems with that laptop. I'm just wondering if it's okay for me to use quotes/other people's experience and provide links to that particular source. I imagine probably not, have to email the admin/site owner and get their permission. If you happen to do something similar like this, perhaps not an aggregator but something similar using content from other websites, how do you make it work? I don't know to me what you can buy for $300.00 from a store brand new is pretty bad, compared to what you can buy used that was the top-model 2 years ago. I suppose that is arguable if say the new models have a smaller dye and the processor uses less power/is cooler. But the performance will probably be better with more ram, stronger processors not this intel Atom crap or Celeron.