That depends. Has the idea been implemented only in one country, or on one continent? Do the creators have the ability or capital to develop strong barriers to entry that would take tremendous capital and/or years of effort to overcome?
Spotting an idea abroad and bringing it to your own geography is a perfectly viable strategy.
Check out resources like SpringWise dot com or TrendWatching dot com (full disclosure - I subscribe to both) to learn about new ideas being launched abroad that you could potentially bring to your own country/city.
Yeah this has worked pretty well in the daily/ group deals space as you really need people on the ground in each locale to push it to business there. Only so many people in so many countries someone like groupon on living social can hire.
I'm always bothered when people tell me an idea I want to work on has already been solved. Imagine if people gave up, and let MySpace keep it's position. There's a lot of crap out there that deserves to be improved.
Spotting an idea abroad and bringing it to your own geography is a perfectly viable strategy.
Check out resources like SpringWise dot com or TrendWatching dot com (full disclosure - I subscribe to both) to learn about new ideas being launched abroad that you could potentially bring to your own country/city.