Most successful startups sell to other businesses but there's no rule of course. Contracts are more lucrative but they're often harder to get and require building a long lasting relationship.
|B2B or not 2B, most important is to find the business model that works best for you!|
B2C is very costly in terms of marketing as you need to build a brand from scratch but returns are potentially bigger. Buzz happens, however not often, and social networks can convey information quickly.
In the end explore both and measure what's more effective for you. Put someone in charge of exploring new business models in any case: that'd too bad to realise too late you missed a great opportunity.