Lots of impressions quickly - why?

[Jon12345]

I am doing some split testing on a website but my statistics are thrown out because I have been getting lots of impressions very quickly, like 200 or 300 in the space of about 10 minutes.

What do you think is going on? Are they robots? DOS attack? Any ideas?

Thanks,

Jon

[Aragorn]

Could be because some bots were visiting your site at that time. Is it still happening?