Unbelivable. Maybe I guess your website is appearing on first page of google for very high searching keyword. Out of all those visits, how many is for organic traffic?
That's great Consult your analytic package to find out what the referring sites where if you havn't already. It seems that a high traffic site did a review of your site but you don't know if the review was positive or negative and imho you should find out.
Unless your site is made for the Digg audience, digg is useless. Some sites though milk and exploit it like crazy. How do you not know where the traffic came from? Was it direct link? It would be very difficult to find out if your link was said offline.
maybe searchia did something that causes the traffic to boost. somehow, It changed in one day. this is normal for some site.
My friend has the exact same thing so he wanted to know. Contacted google becuase it made him a tonne of money so he wanted to know what he did to get that traffic. But they wouldn't tell him. I was gutted for him but I guess it's good that Google keeps this info secret as he could have leaked that and things would be even harder for everyone.
I didn't understand why is this happened. But i guess you were probably submitting your link in many directories and social bookmaker. Anyway, you are lucky. Are your traffic useful? Please, let me know.
Incoming links is best, also make sure its not the use of the magic traffic bot (real software lol) -- Other than that, congrats -- Share as many tactics as you can =o)
What type of website is that? I have a soccer blog which averages 200 visits a day, now it shoot up to about 1,000 visits a day. Probably because of the on-going transfers and trades.