Copying boiler plate posts between multiple networks using Buffer, HubSpot, Sprinklr, Hootsuite, Salesforce or other cross-posting tools is better than nothing, but you can expect about the same return on investment as you put in: not much, says our own Cappy Popp in a recent CMS Wire post.
Understand your audiences in the communities you've built and what content, language and post format resonates most successfully with them. What "success" means should be clearly tied to concrete business-focused goals, not how it's defined in a deck you grabbed on SlideShare or read in a blog post. And hopefully you haven’t "bought" your fanbase through cheap "click to like" ads run in third-world markets or you're going to have a bad time.
Though polarizing, persona-based marketing is an effective tool to help discover which content is appropriate for a community at a specific time. Personas are tied directly to your business goals and "buyers journey," not to the whims of the networks on which you participate. This allows you to craft content that targets different personas at different phases of this process, sales pipeline or conversion funnel.
Everything you publish should provide a tie-in to the next action you want a reader to take. Otherwise what's the point of publishing it? The days of, "oh, we're just testing out this thing called social media to get some followers" are long gone. Cross-posting the same "buy now" marketing copy to five social networks twice a day ad nauseam isn't going to get you anywhere but unemployed.
So do you cross-post to all channels? Short answer: no, not if you can help it. It's not necessary to create custom content for each channel. However, you should use the original content as a starting point. Tailor it to make sure its core messages remain consistent but the language and call to action are appropriate for the personas you're targeting on each network.