It is currently possible for filters (or even slicers) to be preset when publishing to PowerBI.com. From a threat on the recent PBI AMA it was stated that Power BI will be able to be embedded in SharePoint. When that happens, it would be great to be able to preset filters for each embedded dashboard/report rather than needing to set it in the Power BI pbix file first. This way it would allow multiple instances of the dashboard/report to be embedded and filters set for the specific SharePoint embed locations. The use case for this could be a sales situation where there are multiple sales regions all looking at the same report. It would be nice to have the report embedded in each of their team sites and pre-filtered to their region.