Andy Beard started a Google Groups thread asking why Google seems to be handling tagged pages (tag cloud results) in a "fairly random fashion." Andy goes through examples of how Google sometimes indexes these pages, sometimes shows a cache page, sometimes ranks them well and sometimes not.
Google's JohnMu has a fairly long response on the topic. In short, John said he does not believe that Google treats tag pages any different than any other page on the Internet. Let me quote John:
I'm not aware that we're treating this kind of page any different than other pages. A tag page can be a good resource for users, at the same time it can also be that it would make sense to send the users to an article directly instead of having them take the "detour" through a tag page (I imagine it depends on the actual query). In most cases, I would assume that these tag pages are more of value to us in helping us to find the content that is linked from them. If a new article comes up and is listed there, we'll want to go grab that article as fast as we can.
But tag pages can be problematic in many cases because:
- They don't often have very much unique content from your other pages
- Some tags may be very close to others, where the only difference may be punctuation or capitalization
- In a sense, they are a form of search results - kind of
We went through this dilemma when adding our tag cloud about a year ago. Honestly, I find my tag cloud here incredibly useful and relevant for my search experience - so I am glad I allowed it to be indexed.
Forum discussion at Google Groups.