Hyphenated Tags Must be Outlawed
Tags is an indexed-sequential search, not random access
I.E. The tag filters on a major idea. It is supposed to be a quick narrowing of possibilities with a high likelihood of picking up specifics I'm looking for (assuming they exist in the first place, of course). At that point the brain takes over looking in detail at the search results.
As we "engineer" specificity into our tagging system we move toward the idea of a single query to find exactly what I'm looking for. I assert that this bad, anti-tagish. Let's just use SQL for crying out loud.
Are hyphenated tag names transitive?
In the first case I'm "looking for ipod stuff" and in the latter I'm looking for "application stuff". How I think about my search matters.
What is the results implication of including both hyphened-versions? Who knows how the hell the tags were used when at least 4 tags may be involved here! I don't want to know - and I don't have to know if we ban hyphen-tags.
Major points of tagging goodness are:
Very little time spent constructing the query.
There are no semantics & syntax to know about - including implied or assumed semantics of hyphenated tags.
1-off tag proliferation makes tracking favorites impossible.
Specificity is gotten by using multiple tags - and it's syntax free
A broadly cast net so I don't waste my time looking for stuff that was filtered out by too much tag specificity
There is a gross assumption that the searcher knows (a) how to search a rendered web page and (b) search with tag/literal-text in the first place.
Hyphenated tags should be outlawed
I would make exceptions, for example macbook-pro because this does not mean "macbook" or macbook pro". I prefer it to macbookpro, but would defer if it is confusing or non-hyphenation were enforced @ creation time.