Matt Cutts appeared at Search Engine Strategies this week. In addition to talking up the Knowledge Graph and scaring people about the Penguin update, he talked briefly about Google's relationship with Twitter.
First, we linked to a liveblogged account of Cutts' session from State Of Search, which paraphrased him as saying:
Danny [Sullivan] asks ‘Can’t you see how many times a page is tweeted? I can see it, I could call you’.
Cutts: we can do it relatively well, but if we could crawl Twitter in the full way we can, their infastructure wouldn’t be able to handle it.
In a later article on what SEOmoz CEO Rand Fishkin had to say about Twitter's impact on SEO, we also referenced Brafton's version, which paraphrased Cutts as saying:
People were upset when Realtime results went away! But that platform is a private service. If Twitter wants to suspend someone’s service they can. Google was able to crawl Twitter until its deal ended, and Google was no longer able to crawl those pages. As such, Google is cautious about using that as a signal – Twitter can shut it off at any time.
We’re always going to be looking for ways to identify who is valuable in the real world. We want to return quality results that have real world reputability and quality factors are key – Google indexes 20 billion pages per day.
The Brafton piece also indicated that Cutts said that Google can't crawl Facebook pages or Twitter accounts. It was later updated, but this led to Fishkin asking Cutts about that on Twitter, which led to some more from Cutts on the matter.
@randfish also: post-firehose cutoff & post-crawl cutoff, there are >400M tweets/day. Unclear Twitter could/would stand us webcrawling that.