There is no HTML tag to do this. Counters are quite pointless, though. They can be set to any value the owner wants, so they don't give you any information. Because of the delay that often occurs when using an external counter, your visitors may get annoyed with the long loading time of your document. The server's logfile provides a lot more reliable information for you, and you don't have to bother your readers with it.
Many browsers identify themselves when they request a document.
Keep in mind not all browsers identify themselves correctly. And of course, if a cache proxy keeps the Netscape enhanced document, someone with an other browser will also get this document if he goes through the cache. This is explained in the HTML 2.0 specs . Tags are case insensitive, so it doesn't matter. This is just a matter of style.