How important are Alexa ratings?

50 unranked rankings.

Pretty Accurate

....As in it matters, but it really doesn't

That's goofy. You would think they would check it before the attempt to do any kind of link trades if it was that important to um. I am not charging anything to place hard links on ay of my sites and some webmasters have still changed there mind about putting one on it just because of Alexa rating. Kind of silly to turn down any kind of free traffic i think. Every visitor helps.

To base judgement on alexa ranking only: it is stupid, simply because you can go in top 10k by buy every month few $100's woth of popunders who will make zero signup, but grow your alexa ranking sooo much. Look at livejasmin, with popunders they're like a facebook or google there. We also advertised with popunders at times and alexa reached top 10k, then when stopped returned low, but sales was the same really, just hosting bill increased that period

It is however true that lots people look at alexa ranking to decide if do business with you or how you are cool, so you may buy some popunderrs just to keep your alexa ranking cool to show friends. Also if alexa ranking is n/a or 3 millionth, this could be an useful indicator that the site is really dead - but should also check compete.com , google trends and so alexa just one of a number of other tools - these data all together is meaningful.