One of my site had 80 people viewing the site at one time all the time yesterday. Just one after another all day. Massive amounts of visitors for it to have at one time or for the day total. The interesting thing is they appear to have come from google.pl, Poland. Now all of the sudden the traffic is gone the next day. What would have caused the huge spike like that and for it now to be gone?
Have you checked your stats to see if you ranked for a keyword that you don't usually rank for.The search engines update all the time so you may have been bumped up for a bit.
Google.ie has been flicking between two different sets of results regularly for me. One day I rank 3rd for a keyword the next I disappear and then back again. Sounds like .pl was getting good results for you that day and has switched back again now.. You should see it flicker a bit over the next few weeks.. I'm just hoping the good results kick in as the default for me eventually
Someday i get hundreds of visitors from google and other days its not even topping a ton. Just keep doing what your doing