It was and is still trendy. I personally do not use those domains as ccTLD's can get pulled for a myriad of reasons and with a recent ruling [1] some will like

It was and is still trendy. I personally do not use those domains as ccTLD's can get pulled for a myriad of reasons and with a recent ruling [1] some will likely vanish when their corresponding country [2] ceases to exist as in sovereign legal status. I can not think of a technical upside to using .io I should add that being too affordable can also be a problem. Examples would be .info, .me and .xyz among many others were nearly given away for almost free which led to them being abused for spam/malware and thusly getting blocked by many mail providers and some firewall applications. I agree with PaulHoule that the gTLD may not have been available being one reason people use them. [1] - https://news.ycombinator.com/item?id=33091007 https://news.ycombinator.com/item?id=33091007 [2] - https://en.wikipedia.org/wiki/Country_code_top-level_domain https://en.wikipedia.org/wiki/Country_code_top-level_domain