> where do they go from here?
I read somewhere: DDG sees themselves, currently, as an internet privacy company, not as a search engine company. (They say.) The search engine is just one of many tools towards privacy. This might explain why they have not created a real serious crawler to build their own index.
I could see them moving next into either privacy focused messenger service or social network. However both require registration which becomes a problem.
I don't think Microsoft will refuse to renew the search feed deal with DDG. DDG's success helped convince everyone else to use/buy Bing results and Microsoft is reportedly making a profit on this plus sticking it to Google so it's all win-win for MS.