It 100% depends on the goals of the startup. What audiences are you trying to reach, where do those audiences spend most of their time? What social channels are important to your target audience? What topics/subject areas are meaningful to them.
After that, consider what your KPI's and long term goals are for your startup. Are you looking for new user acquisition, brand visibility, community building, etc.? All of these factors would influence the direction you take with your content and promotion efforts.
For most startups, content marketing can probably best be leveraged for large scale PR wins. If you are capable of creating content with a news hook (something large publishers find compelling enough to talk about), you can create large sharing cascades if you can drum up interest in your content through targeted digital PR and influencer outreach. This type of content marketing can drive results in a number of ways, including but not limited to:
1. Brand visibility (which can drive new user acquisition, especially for apps or SaaS companies
2. High authority linkbuilding and social sharing, two key factors in improving a websites authority, and thus organic rankings. For companies relying on organic search traffic, this is especially essential.
3. Direct sales. This type of content marketing usually means pushing your content to more tightly controled audiences (usually through very targeted paid channels like Facebook ads) The content for this is often much more sales directed (though it must still provide good value). Things like whitepapers, case studies, industry thought leadership, etc. is what applies here.
There is much more to all of this obviously, but it all starts with very carefully defining short and longterm marketing goals, and then devising an effective strategy around those goals and associated target audiences.
You can email me at Kristin@frac.tl, if you would like some more info, or to see what can be done by an agency that understands the ins and outs of content marketing, with case studies and examples to prove it, check out www.frac.tl