Google announced that as another in its series of product-prunings, it was going to shut down iGoogle, a personalized startpage that let users organize widgets for feeds, content and Google services. Alistair Croll has an interesting post today where he suggests that Google could turn Google+ personal pages into an iGoogle replacement. He goes on to sketch how Facebook might have a tough time using a similar, app-based strategy to encourage monetization. (And he gives Twitter too much credit for ad success, while pointing to a nice cover story on Forbes about LinkedIn’s money-making abilities.) Years ago, I wrote that social networks would steal away some audience segments from portals like Yahoo and AOL as the web startpage for consumers. We’re working on a GigaOM Pro report on social network usage and evolution, based on our U.S. consumer survey, that should post next month.