We at ecigarettedirect.co.uk who run the Ashtray Blog, have put together research from numerous sources on the topic of whether electronic cigarettes are a gateway to smoking.
The results showed the vast majority of e-cigarette users are either current or previous tobacco smokers and only a very small percentage (0.1%) of users were not tobacco smokers previously. This suggests that the majority of electronic cigarette users are using them as an exit from smoking, not to. The infographic also covers the reasons people smoke e-cigs as well as their effectiveness against nicotine replacement therapy (which is almost twice as much!).