Online social networking has significantly increased in popularity over the past several years, with sites such as Facebook now boasting over 300 million members. Scientific gateways have much to gain by incorporating social networking functionality. There are a variety of approaches for integrating social networking functionality in scientific gateways. These include integration into existing general purpose social networks or developing custom social networks that can be hosted by a third party or in-house. In this paper we compare these different approaches and relate our experience in applying these approaches in the development of GeoChronos, a collaborative gateway for earth observation scientists.