jdMorgan - 8:24 pm on Aug 11, 2009 (gmt 0)

It could be called cloaking -- or more accurately, IP- or user-agent-based content delivery.

However, it does not sound like it is "cloaking with intent to deceive" either search engine spiders or visitors. Generally, when search engines talk about cloaking penalties, these penalties apply to "cloaking with intent to deceive".

It would make no sense to punish a site (punish its URLs, really) just because the content changes based on the User-agent or requesting IP address. Imagine for example if Google punished sites for serving different content to mobile devices, gaming devices, netbooks, tablets, notebooks, and PCs/Macs. Or if they punished sites for using IP- or User-agent based delivery to serve different-language content to different areas of the world. They would punish most of the major sites on the Web, including themselves!

I doubt that a few extra lines of text are causing you trouble, unless it contains a bunch of gibberish or excessively-repeated keywords. You can bet that the search engines are aware of your alternate content (unless you subscribe to a "real-time robot IP address identifier service" for cloakers to prevent that), but I doubt that this is the cause of your trouble; I use an approach similar to yours on a couple of pages to help visitors find what they are actually looking for (as opposed to what they initially searched for), and it doesn't seem to affect those pages' ranking.

Jim