Google, Yahoo start from scratchIf at first you don't succeed — and you can't manage to buy someone — try, try again. That's what Google and Yahoo, realizing the failure of their social-networking products, are doing. Google's Orkut is a nonstarter outside India and Brazil, and Yahoo 360 is, well, a nonstarter everywhere. Here's how the two giants of the Web are trying to fix their social inadequacies.Google's entrant is Socialstream, a Google-sponsored project at Carnegie Mellon University, which, instead of serving as a social network itself, attempts to unify multiple networks. That's a product that users, drowning in multiple logins and passwords, could badly use. And it plays to Google's strengths: Rather than trying to get users to contribute content to a new network, Socialstream just uses software to bring existing information on the Web together in one place, much like Google's Web search. Google, Yahoo start from scratch (Screenshot by Google Operating System) Less is known about about Yahoo Mosh, a site that's live internally on Yahoo's network but blocked from outsiders. But I did find this intriguing trace: When you google "mosh.yahoo.com", you turn up a couple of results on YouTube. The inbound links from Yahoo Mosh to the YouTube videos suggest that Yahoo Mosh is a combination of profiles and bookmarks — a mashup, in other words, of Yahoo 360, Yahoo's failed MySpace clone, and Del.icio.us, Yahoo's popular bookmarks website. "A social network so user-friendly, even your mom knows it's redundant!" says Valleywag contributor Nick Douglas. If you want to know what Yahoo Mosh's internal beta testers are watching, here's a clip: