Do you really believe that BS? that usig gmal to buy links or such stuff can hurt you? really?
Ok, I hope everybody understands that google employees don't personally rad your email to find blackhat stuff
You can say: "It's 100% automated process, google just extract links from emails and use that to find blackhatters"
Ok let's ASSUME that (still great BS)
All I have to do is use my competitors website links in gmail letters with titles like BUYING LINKS FOR COMPETITORDOMAIN.COM!!1
And my competitor will be penalized
Do you really believe that?
A part of Google's business model is extracting personal information from users of their services and using it for advertising purposes. They do not charge people a fee to use their products, since the personal DATA they collect is much more valuable. It's similar to internet marketing - the money is in the list, and Google is building the biggest list in the world, profiting from using the information internally or selling/sharing it with other organisations.
Now of course they do not have employees personally reading your emails, in the same way that they do not have employees manually goto every website on the internet to determine where it should rank. They use huge amounts of computing power to extract, analyse and eventually monetise your personal information and Gmail is one of many services which does this:
From Google Privacy statement:
"We use the information we collect from all of our services to provide, maintain, protect and improve them, to develop new ones, and to
protect Google and our users. We also use this information to offer you tailored content - like giving you more relevant search results and ads."
The part "protect Google and our users" is open to interpretation and conspiracy. But it would be foolish for them not to use the data they gathered to help prevent manipulation of SERPs.
There was an
incident earlier this year when an SEO asked Matt Cutts for help with a reconsideration request for her client's payday loan website. Matt Cutt's response:
How does Cutts and Google know that her client has "signs of
long-standing mass deliberate spam"? They may not have come to the conclusion from analysing Gmail communications, but what other information did they use ( and was it collected from other Google services?) to conclusively identify them as serial spammers?
Knowlege is power. If you have use Google services whether currently or in the past, then they have more power over you than you realise. If you are serious about SEOing on Google, then surely should be serious about doing everything you can to cover up your footprints from them?
