OMG, has this been going on since 2013?! I only just found Geneio (in that spelling) on my iMac a couple of weeks ago, and in my (sorrowful) experience it's much more aggravating and devious that contributors to the discussion so far seem to recognize:
(1) it's worse than so-called adware, a) because Genieo has never inserted any kind of ad on any of my devices, and, b) because it never showed its face at all until I recently introduced a NetGear extender into my local wi-fi network. Worse yet, it did make itself known, apparently, by hacking itself into the extender, from which it began inserting requests for passwords ⚠ every single time I tried to open a new app, whether on my iPhone, iPadAir, or MacBookPro, though not on my iMac — whether or not the respective apps were password-protected or not, and for that matter, 'allowed' the app to start irrespective of what I did, including swearing at it. This makes Geniero a PHISH, right?, and PHISHES is what MacKeeper identified it as.
(2) it's insidious in the extreme. MacKeeper detected and subsequently deleted six files on my iMac>user>library folder identified as phishes, as well as a Geneiro installer package lying in my download folder. I suppose I had somehow mistakenly downloaded that installer by accident, or else it snuck in some other manner, but I definitely did NOT ever operate the installer package by clicking on it and moving the resulting icon into my applications folder. Nor was there a Geneiro.app anywhere, though there was a Geneiro-uninstaller, I don't remember where — which I, like others, did not trust and deleted by hand. The evidence I offer for the assertion that the G-phish had hacked itself from my main computer into the NetGear extender is a) the fact that the latter did not behave as it was supposed to by creating a new extended local network with _EXT added on the end, but rather invented an entirely different _EXT network name which I was invited to join, and stupidly did — (this I have discussed with NetGear support and they have confirmed that the extender should not have done so), but also b) because SafeMac's AdwareMedic advised me that hacked extenders could very well be the locus of the problem, and c) because the problem disappeared once I had disconnected the extender and reconnected all my devices to my original local network.
(3) Worst of all, Geneio's insidiousness continues: a) I find that the Genieo installation .dmg, which MacKeeper deleted yesterday, as re-duplicated itself and has once again placed itself in my download folder, from which it resists dragging to the trash, reduplicates itself again and again, and also resists, up to an extent, secure emptying of the trash! MacKeeper informed me, in a banner, that Genieo cannot be deleted because of a permissions problem (apparently it's read-only) but only quarantined, and iMac's finder (in Yosemite) went so far — yesterday but so far not today — as to identify the installer as a separate device, not on my computer but on equal footing with it. Needless to say, I resisted the temptation to click on that icon.
(4) Finally, it's mendacious. Though I have never to my recollection opened the website identified as 'Geneio — your newspaper style homepage' (though I suppose I may have done so, originally; maybe that's how the whole thing started), Safari's history menu routinely falsely lists that link as one which I have visited, just daring me, so to speak, to go there. (My iPhone 6's Safari history menu contains the same false listing).
I could add that I have been experiencing a serious problem with Word 2011 during the same period of time, though it could be unrelated. Word refuses to allow me to close about three files that I opened weeks ago, closing itself down instead and then re-opening with the same problem. Apple should be well aware of the problem by now since it's been reported umpteen times, but nothing seems to help.
