We all know what good Alexa traffic rank is important in order to attract more partners, more advertisers, etc.
Because in Nigeria - Alexa rank perhaps is they only accesible way to measure how popular some site is.

But you must be extra careful when taking decision based just on Alexa traffic rank, because there are hundreds of tools allowing to get super rank just for few dollars. And of course this rank will be fake. It will be generated even without redirecting of traffic to the site. Simple some guys discovered vulnerable spots in Alexa code and can generate any rank without sending traffic.

Some of my friends already were dumped this way. They paid a lot of money for advertising on sites with rank below 300 in NG...And in exchange they got zero clicks.

So when you are thinking about buying ads from some site, don't forget to check some additional things besides checking Alexa data. ALWAYS check part: "Upstream Sites". For example in this Alexa profile http://www.alexa.com/siteinfo/mobofree.com#trafficstats you will see, that upstreaming sites are Facebook, Twitter, Yahoo, Google, etc. So you can presume, that everything is ok with this site.
But if you see something like AlexaBoostup, Alexabooster...don't waste your time and money. The good thing is that most of those services, generating alexa rank contain word "alexa" in their name. So they can be easily identified via "Upstream sites"