You can use it for omission or hesitation, but is it too annoying?
Don’t Use Ellipses to Change the Meaning of a Quotation
It’s wrong to use an ellipsis to make even a subtle change to the meaning of a quotation.
Integrity is essential when using ellipses this way. It's acceptable to tighten a long quotation by omitting unnecessary words, but it's important that you don't change the meaning. For example, the original quotation points out that Apatow hands over writing and directing to a protégé. Leaving out either “writing” or “directing” would change the meaning of the quotation, and even though it’s only a subtle change, it’s still wrong.
It would also be wrong to leave out the part about it working better than “Funny People,” another Apatow movie. Again it’s a subtle change in meaning, but to say it works better than “Funny People” is different from just saying it works.
The E-mail Ellipsis
Now, on to the other use of ellipses that you frequently see in e-mail: the ellipsis that’s used to indicate a pause or a break in the writer's train of thought. Many people have written to me to say that they find this kind of use annoying, but a number of style guides say that ellipses can be used to indicate a pause or falter in dialog, the passage of time, an unfinished list, or that a speaker has trailed off in the middle of a sentence or left something unsaid (1, 2, 3, 4). For example, The Chicago Manual of Style states, “Ellipsis points suggest faltering or fragmented speech accompanied by confusion, insecurity, distress, or uncertainty.” The Manual contrasts ellipses with dashes, which it states should be reserved for more confident and decisive pauses.
So, it is allowable to use ellipses to indicate pauses or breaks in the writer's train of thought as you see so frequently done in e-mail, especially where a break is meant to feel uncertain. Nevertheless (and this is a BIG nevertheless) most people who use ellipses in e-mail overdo it—a lot.
You should not replace all normal punctuation with ellipses. You should not allow the sweet lure of ellipses to muddle your ability to write a complete sentence. To quote the book Grammar for Dummies, “Using ellipses in this way can get annoying really fast.”
The author of one of my favorite books, Punctuate it Right, feels this way about writers who use ellipses to imply that they have more to say: “It is doubtful that they have anything in mind, and the device seems a rather cheap one.”
So, use ellipses to show hesitation or a trailing off of thoughts if you must, but use them sparingly, and know that although it's grammatically correct, it's considered by some to be annoying and cheap.
Finally, there are some other special circumstances where ellipses seem to be allowed.