If the trend is toward greater fragmentation in social media, then what does this mean for companies like Share This?
RRW noted the upgrades to their widget, but have they missed a large piece of the puzzle? particularly when fragmentation and decentralisation are becoming all the rage?

The problem is, people belong to different communities for different reasons, and share different things within them – different content being suitable for different communities – everyday becoming more niche in their point of focus and congregation.
So clearly, adding more and more buttons is an unsustainable direction – even providing a search box would seem like a bad idea. What is required is to have detection of the communities that you belong to in the browser, and the standard interface being default when this can’t be detected. The other alternative is to have a community upload section on the share this site which would allow access to emergent communities. The default buttons could then be determined by sharing user defined communities, sharing clicks per page.
This would allow more tailored and relevant niches grow alongside the content relevant to those communities, providing the user with more relevant communities choices on the initial interaction, but also providing content with more targeted and relevant audiences.
As the web expands and online communities grow, it is likely that they will become far more numerous and fragmented (much like media is fragmenting today). The main thing holding back a rapid change to this trend is that currently the tools for building your own social communities still leave a bit to be desired. While Ning provides a great platform for managing your own community, it lacks Facebook connect, which would encourage growth, however, more importantly, it lacks the ability to truly customise to provide tools that solve whatever the issues are that a niche community requires.
There are some things that are universal between communities online, but almost always there is one specification that is unique to that communities needs. Allowing for easy widget integration in these communities would accelerate the growth in niche communities. Open source frameworks that clone Digg are readily available and are providing the basis for many new communities like www.saysthou.com and www.dotnetkicks.com etc.
The reasons for the emergence of communities like this are due to different cultural reasons with each tribe, and due to tribes being victims of their own growth and unable to support egalitarianism. Digg was significantly better when it was young because the Tribe was united with one common cause - remove the need for editors in mainstream media, let users drive the 24hr news cycle. However, as it grew, it became apparent that all users were not equal, as groups of influencers worked in concert, – the disenfranchised left and found new tribes, or went back to old tribes (like www.fark.com where I actually like the editors).

The other solution was for these people to create their own tribes, and to address the issues that made them leave the former. Like Digg addressed the needs of those that left the mainstream media tribe, emergent tribes will address the issues that plagued the one before them in an evolutionary, and Darwinian fashion towards a truly egalitarian framework for the distribution and allocation of power/ influence with respect to a shared ethical framework.