Since the start of the month we've noticed some very strange Slurp activity in our logs. On four seperate days (all Thursday mornings) we had Slurp bombarding our site for about an hour with over 1000 requests, all of these being referals from our Overture Ads (the URLs include our ppc tracking parameters etc). For each referal Slurp requested the same three pages (the landing page, the page it 301s to and then a page linked from that page). Unfortunately I havn't been able to check with our PPC team to see if the clicks correlate and we're actually paying for them.
My first suspicion was that this might be click fraud, as the IP addresses are different to other Slurp IPs that we saw crawling at the same time (with usual behaviour). The new IPs were: 220.127.116.11 18.104.22.168 22.214.171.124 These all check out as Inktomi.
This was actually mentioned a while ago (http://www.webmasterworld.com/forum35/3294.htm) but no one replied to the post. I was hoping that maybe someone has seen a similar thing or can shed some light on this?
It would also be nice if someone could confirm whether or not these referals should be costing us as click?
No changes have been made to our site and there are no spider traps. The spider pattern is always the same, they hit our PPC advert landing page and then spider through to the next two pages.
The only place I can work out where the entrance page URLs (with our PPC tracking codes) are being found is by following the 302s from our paid links through Overture. I'm not sure how Overture works but wouldn't this be tracked as a click?
I think they have IP ranges that are excluded from the PPC systems, such as their internal networks IPs, not sure though. I guess you should really check with their customer service mentioning the IPs to be sure.
I've had EXACTLY the same problem. It was noticed last week in the web logs, but then looking back through logs over the past couple of months show an abnormal amount of Slurp activity between 07:00 and 14:00 every other Thursday (as well as on a couple of Saturdays). Each time it's about 1,000 visits from the Inktomi IPs.
Every time Slurp arrives at our site, it uses a different Overture keyword (like emomilk we used our PPC tracking in the URLs to identify this). Looking at our Overture stats for the days this happened shows no extra clicks. Some of the keywords used by Slurp to get to our site have never been clicked according to Overture's stats, so we're pretty sure this activity isn't being charged for.
I mentioned this to our Overture account manager last week and we're still waiting for the official line on what's going on.