Added 1: Harry, can you give me an example? (I don't think I mix these two, though I do mix a lot of other things.)

It could just be an error in the french as well, but I saw it in Toën's notes on stacks and thought that it could be a similar thing like what happened with "associated with" and "associated to", but as I admitted, this was really just speculation =).

Added 2: To me, the alternative "le faisceau associé avec le préfaisceau" mildly suggests a symmetric relationship, which is not true in this case; I guess "avec" is sometimes closer to "together" than just "with."

I just know that the form I stated is correct in French but translating "à" as "to" returns an ungrammatical sentence in English (cf. JS Milne's page complaining about these things).

Added 1: Harry, can you give me an example? (I don't think I mix these two, though I do mix a lot of other things.)

Added 2: To me, the alternative "le faisceau associé avec le préfaisceau" mildly suggests a symmetric relationship, which is not true in this case; I guess "avec" is sometimes closer to "together" than just "with."

Of all places, of all people, you should know it's not "unique visitors" it's "distinct visitors", dammit!

Nothing is more annoying to me than replacing "satisfy" with "verify". I've seen this in French as well, and I wonder if they both can mean the same thing in French (based on the below, it's not such a huge stretch, although I haven't really checked).

The phrase, "Le faisceau associé à un préfaisceau" is grammatically sound in French (where à here means "with" in this context), and it seems like the usage of "associated to" in mathematics in English comes directly from mistranslations of things like this.

(Sorry, I couldn't resist!)

This shouldn't be an issue. People will also use MO at their homes. I use it even on my mobile. By referring to usernames using some clever sequence of greps, etc., one should be able to find out unique visitors.

And google analytics will anyway given unique visitors, even with shared IP addresses. They manage it with cookies.

Are there more or fewer unique IPs than unique visitors?

I don't know how to get a list of IPs from Google analytics, though it must be collecting them. If somebody knows how to do this, please let me know. FWIW, the MO database has 68,386 unique IPs appearing in it (surprisingly high, I think). That only counts IPs of people who have done something (though it's a weaker form of doing something than before ... for example, registering an account counts as doing something).

Edit: Replaced unique with distinct as per voloch's suggestion.

It undercounts when multiple people use MO from the same computer and when people use MO without javascript enabled.

Or weird people like me, who run firefox with the NoScript extension and haven't enabled google analytics.

@Anton- I can't speak for anyone else, but I certainly enjoy traffic information.

I'm happy to post whatever aggregate data anybody wants to know (that I can easily get my hands on). I have access to a few sources of information that random users can't see:

• The complete database dump. This is useful for answering questions about actual use of the site. Things like "what is the average time between when a question is asked and when it gets its first answer?" Most such questions can actually be answered by looking at the public dump.
• Google analytics. This is useful for answering questions about how people browse the site. I can use it to answer questions like "what part of the world do users come from?" and "how many pages does the average visitor look at?"
• Google webmaster tools. This tells me how much googlebot is looking at MO, how many URLs have been indexed, what Google thinks are important keywords, and what pages have the most links to them from elsewhere.

The "4000 unique visitors per day" is based on analytics. The "1600 people have actually done something" is based on looking at badge counts: the [Teacher] and [Student] badges are only awarded once and anybody who posts a non-spam question or answer will get one of these badges.

For example, do you know how many unique visitors we've had total?

252,246 according to analytics. Uniqueness is measured by a cookie, so this overcounts people who have cleared their cookies or used MO from different computers. It undercounts when multiple people use MO from the same computer and when people use MO without javascript enabled.

Again, will Anton be able to produce some helpful "actual data"?

I'm not sure what sort of data you're interested in. See this other thread for some discussion of our lurker population. The numbers aren't so different now than they were then. About 1600 people have done something on MO, but we get about 4000 unique visitors per day. The average length of a visit is now about 7.5 minutes.

Those who have blogs should be familiar with this; there are a lot more blog-readers than blog-writers.

Again, will Anton be able to produce some helpful "actual data"?

I mean, it isn't the case that the person who was talking to me googled my name and found my MO userpage. I came to know of MO's popularity via honest gossip. Like, I'm MO's secret agent in the populace.

Have others observed this phenomenon? There is a chance that it just my (illusory) feeling. For instance, a cat lover might find that the whole universe is full of cat lovers. Or, an owner of a Mercedes-Benz would keep noticing other such cars.