Ask HN: How would you effectively break up an internet monopoly?

To me, it seems that breaking up Standard Oil is very different to breaking up a company like Google; while Standard Oil could be broken up into businesses based on geographical regions and physical resources, Google has data and IP which isn't easily divided (and is quickly coalesced too). Moreover, any divided Internet monopoly could scale rapidly back to a monopoly with the help of an IaaS provider. What differences would have to be considered? What would the breaking up of Google look like? Have there been any real world break ups of Internet monopolies?