Experiment Results In: Does Google Index Gmail Links?
I set up an experiment to test whether Google crawls and indexes links in Gmail.
This was of particular interest to me, and brought to my attention by the person who manages the Google Search Sucks blog. So I have to give a tip of the hat to this blogger for giving me the idea for the experiment.
Here is a description of the experiment:
Hypothesis: Google might be indexing links in Gmail in order to give its PageRank algorithm more link popularity data. Google might do this because most people using the Internet are not publishing web pages. These people “publish” links by sending them through email and IM.
Experiment: I published an orphaned page (you can’t get to it from any other link) and sent a few emails through Gmail (from Gmail to Gmail) with the link in the email. I gave Google about 2 months to find the page.
Results: Google did not index the page, suggesting that it does not crawl Gmail for links.
Experiment Limitations: I only sent two emails, not hundreds, which may or may not have an impact.
Why This is Important (to me)
If Google did indeed index links in Gmail, there would be privacy issues. For instance, employees sending links to web pages not meant to be seen, or to files on FTP servers for download. Hmm, that wasn’t a full sentence. Oh well. Damn, another one.
There already are privacy concerns with Gmail - the fact that Google reads your email and serves up “relevant” ads has alarmed a lot of people.
Personally, I have let go of that concern and now have a very different opinion: I enjoy looking at the ads Google thinks is relevant to me. In a recent email, Google’s ads suggested that they think I need a divorce lawyer and a private round of funding. In that email, a friend was telling me about someone he just started dating (OK: do we really need to trigger divorce lawyer ads for someone who is excited about a great second date?). The friend also described his work stabilizing the financial position of his company (OK, I see the funding ads as relevant there).
On another topic: Gmail does a great job of filtering spam (compared to Yahoo!, which still delivers me about 10 emails a day that mention Viagra or Cialis in the subject.)
Gmail neatly places spam in the spam folder, and serves contextual ads in them, which is a bit curious to me.
Long story short: Google does not appear to index links in Gmail. I say, “appear”, because the experiment was small in scope.