Executing an idea, means monetizing that idea
adii.me
adii.me
Obviously having a well thought through idea of the "end game" in terms of monetisation / business model is a powerful thing, but given the tendency of start-ups to adapt and pivot, this can overly dominate thinking early on.
The simplest case studies are the ideas whose value is linked to the size of the community / user base. eBay were able to get round this by only charging the community once it was large enough (ie I imagine they already had the monetisation "end game" in mind) - but twitter, facebook? Not so much.
So yes, if you're building a platform of sorts, then by all means skip the monetization part initially. Skipping it though, does mean you incur the risk that you won't be able to monetize properly later on. Simply saying you'll figure out the revenue later on, is a bad excuse for not having a plan in place before.