In addition to what @babibalubi said above, it is important to know HOW Alexa ranks sites. Ranking is based on user visits AND pageviews, not just basic traffic numbers.
For example, that big drop in January shown in the OP image is clearly due to the Forum changeover. The forum generates a lot of pageviews for Fiverr but not necessarily from buyers. It is likely that the Forum is a large part of that ranking.
Secondly, if reduced pageviews can cause a drop in Alexa ranking then actually, a good search algorithm will actually DECREASE the Alexa rank as people will find what they need at the first attempt and stop browsing so much! (Let’s not discuss the algorithm again, I’m just giving an example of how misleading Alexa rank is).
Ever wonder why those clickbaity sites like Buzzfeed etc split their articles into galleries and multiple pages? This is why; it helps manipulate Alexa rank and Google Analytics stats by forcing people to view multiple pages which is seen as positive by the statcounters. In reality though, it is just an irritation for users.
Before you decide to start applying this manipulation on your own site, remember that every time you try to fool Google is a risk - their next update could target sites that do that very thing!