The titles of poems can have a variety of purposes (or possibly purposelessness).
Sometimes they are the last thing written. Sometimes they are the first thing. Sometimes they will be an “untitled.”
A title can be brief. A title can be one word, a phrase, a sentence—a title could push the boundaries of normative forms of titles (even employing various forms of punctuation).
Some titles describe the form the poem is in or tradition the poem is referring to or borrows from, as in sonnet, sestina, ghazal, ode—so forth.
Sometimes they are the first line of the poem (in my opinion, an interesting tactic indeed, but a lost opportunity to say something else).
Sometimes they are a borrowed phrase from the poem (yet another form of lost opportunity, and, in my opinion, can place too much stress on the phrase as what the poem can be reduced to—yes, reduction is a danger in all titles, but such blatant repetition seems to present the phrase as an especially important organ in the poem [some might say heart], while all the organs should be treated with importance; I worry that singling out a phrase diminishes attention to other parts of the poem).
Sometimes titles are the key to making sense of the poem’s context. The identity of a speaker, the scenario, what is at stake—all or one of these or some such other detail can be used to reveal what the poem itself does not reveal. A title can be seen as a place for the explicit.
Sometimes titles seem spoken by a speaker separate from the speaker(s) in the poem—as if some sort of third (perhaps person) omniscient. And this outsider perspective, in some way, is supposed to provide credibility. You are to trust a title. (Have you ever not?)
On the whole, titles seem to be approached (by reader or writer) as a genuine/intentional effort at informing the reader (even if that information is minimal or ambiguous).
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What do you think of the process and purpose of writing a title? Do you agree with my opinions or am I too harsh?