Lets have a look at email
Questions about email software and email software configuration. Questions about webmail are off-topic.
Again, tells us pretty much nothing about email, but also contains irrelevant meta instructions about off-topic nature of webmail.
The premise of this question is not just wrong but DANGEROUSLY wrong and DIRECTLY contradicts advice on the blog:
http://blog.stackoverflow.com/2011/03/redesigned-tags-page/
Avoid generically defining the concept behind a tag, unless it is highly specialized. The “email” tag, for example, does not need to explain what email is. I think we can safely assume most internet users know what email is; there’s no value in a boilerplate explanation of email to anyone.
The other four guidelines there, which are all important and should be taken to heart:
The excerpt is the elevator pitch for the tag.
Meaning "convince me this is the right tag for my question", not "explain to me what email means". If you have a question about email and you need someone to explain to you what email is, God help you.
Avoid generically defining the concept behind a tag, unless it is highly specialized.
Concentrate on what a tag means to your community.
For “email” on Super User, mention desktop email clients and explicitly exclude webmail, as that would be more appropriate for webapps.stackexchange.com.
Provide basic guidance on when to use the tag.
In other words, what kinds of questions should have this tag? Tags only exist as ways of organizing questions, so if we don’t provide proper guidance on which questions need this tag, they won’t get tagged at all, rendering the tag excerpt moot.
The idea that the email tag wiki should explain what email is (or that the excel tag should explain what excel is), is completely incorrect. In the case when the topic is obscure by the standards of the particular site then it might be OK to explain what it is, but for things like Excel and Email on Super User -- there's no way these need to be explained beyond the very briefest three word descriptions.
