26 replies to this topic

[chrishirst]

It seems to me that if Google was as aggressive in its filters/penalties that some of these 'other forums' suggest, that the top ten sites on the results would all be sites with only one link to them and every other site would be 'blacklisted'.

That just about sums it up, it's just a shame that many others aren't prepared to see the visible indications of just how many of the "facts" are obviously not.

This whole C Block thing sounds like it should be added to the list of search engine myths, along with keyword density and all those others.

Yep.

[SeanW]

Another place this came from is the Hilltop paper, one of the authors works for Google:

www.cs.toronto.edu/~georgem/hilltop/

We define two hosts as affiliated if one or both of the following is true:

* They share the same first 3 octets of the IP address.

And, speaking as a guy who deals with networks for a living, it's not a class C, it's a /24. There are many networks that meet the above criteria that aren't a class C (anything with a first octet <192, for instance).

*edit* The idea isn't to penalize sites that come from the same /24, it's to weight their contribution when calculating which of the set is the "authoritative site".

Sean

[Jill]

Welcome SeanW!

[CaliforniaGirl]

I agree somewhat with Jill. This is all very speculative. However, I did read the reference to this in the Hilltop paper.

In general I do not think it is too much of an issue, unless it is excessive and unnatural. I have had a recent experience with this causing a site to be banned in Yahoo.

I think it would be a bit rare but it can happen. So I did a little research and wrote a very short article about this. Can I post the URL?? www.seofever.com/knowledge/independent-back-linking-network.htm

My theory anyway...

CaliGirl

[matt621]

With all due respect to the previous posters and admin, I disagree with the information given in this thread. I have tested this myself and there is no doubt having links on the same c block IP hurts your ranking. I have moved several sites to separate class c blocks and watched over the past year the PR and SERP improve. You can take that to the bank.

[Jill]

I have tested this myself and there is no doubt having links on the same c block IP hurts your ranking.

Yes, indeed. If you're trying to trick the engines into thinking that you don't own all the sites in question, then it could be a problem.

But we don't believe that's a good idea in the first place, therefore it shouldn't matter if you're sites are all on the same server.

[profitability]

Is there an official position from Google or Yahoo on this issue? Any actual statistics?

[Michael Martinez]

The official position from Google is that they do not -- I repeat -- they DO NOT disregard links coming from the same Class C IP blocks. Google representatives have stated clearly and specifically they are NOT discarding links based on Class C IP addressing.

Anyone who thinks they have seen otherwise is misinterpreting results, because I assure you, I am doing just fine with multiple links from inside a single Class C IP address.

It would be contra-productive for Google to follow everything indicated in the Hilltop paper.

[Jill]

Is there an official position from Google or Yahoo on this issue? Any actual statistics?

No, why would they have an official position on it? It's really not something for them to comment on. That would be like telling their algo!

Like everything in SEO, it's common sense if you ask me.

[Randy]

Welcome Matt !

I have moved several sites to separate class c blocks and watched over the past year the PR and SERP improve.

Over a whole year?

Me thinks there may be a bit of confusion over Cause and Effect. There are so many other possibilities that with the details missing I simply cannot accept a blanket statement that the IP change was the root cause. Especially when lots of folks like myself and Michael have evidence pointing to the contrary.

Now if you really wanted to test your theory, move all of those sites back to the same Class C to see if there is an immediate effect. If it's an IP thing, the drop should happen quickly.

[Jill]

Now if you really wanted to test your theory, move all of those sites back to the same Class C to see if there is an immediate effect. If it's an IP thing, the drop should happen quickly.

That would be a great test!

[DanThies]

The way IP addresses are allocated now, having the same /24 or class C block doesn't necessarily imply any kind of affiliation at all. Having the same IP address doesn't even guarantee that two sites are affiliated.