No there isn't. The official line is that there is no upper limit on the amount of Adsense sites you can own. But what does this say about Google? It does seem as if there is something a little suspicious about the way Google is operating.

In their ‘terms of service' (TOS) they clearly state that publishers that use their ads must ensure that their material, to quote; ‘…does not breach and have not breached any duty towards or rights of any person or entity including, without limitation, rights of intellectual property… or rights or duties… under consumer protection'. In simple terms, you must ensure that you have the authority to use the material in your site or that the material contained within your site is your own.

Google also forbids the use of auto-generated sites to display their ads.

But then why hasn't Google put an upper limit to the amount of pages a single webmaster (or even a team) can own? Is it because Google is a business and like all businesses it wants to make as much money as possible?

What is the true underlying ethos of Google? We know that it is physically impossible (even for a team) to create thousands of original sites, full of rich informative content. The researching, planning, organization, development and creation take too much time. No publisher can create a thousand content rich sites by themselves.

We know this and so does Google. The only way that such a huge numbers of sites can be created is through automated means. Through automated website generation material can be siphoned off other sites to create content… without limit. The potential to create junk and make money of it is huge. And the opportunity has been too attractive to miss out on for some webmasters. But this method of creating sites is in clear breach of Google's TOS. Obviously, no authorization can be sought for the siphoned content and none given for the creation of auto-generated sites.

Yet Google haven't put a cap on the number of sites a single publisher can use to display their ads. By not doing so, Google are inadvertently encouraging the use of these ‘black hat' methods of using its service by failing to even suggest an upper limit. They are giving many publishers free rein to spam the search engines and pollute the websphere with constantly rehashed material. Damaging the core of Google itself; its search engine.

Google has, in the past taken strong action against publishers who continuously use automated methods to create their sites. But these actions seem futile, in light of the fact that Google themselves have taken no action to put a cap on the number of sites a publisher can use for Adsense.

There is the remote possibility that this loophole is deliberate and it exists so that it can be exploited by those webmasters that are willing to take the risk. This would mean that that there is a darker side to Google's business operations and if that's the case then Google are playing a risky game. They have to carefully weigh up the short term financial gains of leaving their Adsense scheme open to exploitation against the long term damage it could cause to the stability of its search engine. The integrity of their search engine is crucial to the long term survival of Google. If Google wants to remain robust and competitive it has to tighten up its rules and do the sensible thing by putting a cap on the number of sites an individual can use to advertise their ads.