ye PR and Alexa dont relli mean neting there just indicators to people buying your site....if selling your site it would be beetter to sell it as a PR5 site rather than a PR1 site.
Yes it is useless but most of the webmaster ask for alexa ranking , they think that good alexa ranking must be receives too much traffic comparison to others .
well,alexa is just for checking your popularity, it vary on traffics that the site has. Its still worthy but not in SERP.
Yes you are right we have seen that many user buy adds on good alexa ranking sites , But this is also true that few guys know how to improve them with bad tricks . So i don't think so it is worth buying adds based on alexa ranking only . We should ask them for Google analystic reports also .
mine too it increased by 78000 although I never cared for it but after this thread I happened to check it and here I have it. INCREASE