Somebody down in the "Cross-Genre" thread asked me what I thought the difference was between romance novels, ChickLit and Women's Fiction—was the designation "ChickLit" just trying to be "more literary" than the usual image of romances? Well…
Frankly, I'd be surprised as heck if anybody regarded ChickLit as "more literary" than anything. Mind, I've read a couple of terrific novelists whose books fall into (or at least are sold as) "ChickLit"--Marion Keyes, in particular; I'd recommend her books to anyone, but they're certainly packaged as CL. Too bad if that kept anyone from reading them; they're beautifully written, with wonderful characters—great humor, but great sensitivity to underlying tragedy as well, and an understanding of what's necessary for redemption.
ChickLit does usually have a strong central romance. I think the major differences (aside from marketing--sometimes that's the _only_ difference) between ChickLit and straight romance are:
1) time period. If your romantic story is historical, it can't be chicklit. Ergo, it's either historical romance (no demand for accuracy—which is not to say that some authors are not scrupulously accurate; they are (Jo Beverly and Mary Balogh come to mind), but readers don't demand it—and a fair amount of explicit sex) or historical fiction (considerable accuracy, relatively little sex, or sex done by reference rather than exposition. (Cf. Margaret George) and a lot of the story not having to do with the central relationship).
2) ChickLit is _ipso facto_ contemporary because of the other big difference: morality. In a standard romance, the heroine doesn't have a sexual relationship (other than rape) with anybody but the hero. In ChickLit, she sluts around pretty freely, with no evidence of reservation or conscience, until Mr. Right makes himself known. (I recall seeing a re-run of "Sex and the City" recently, in which Carrie Bradshaw is typing and musing about the discovery that she and all of her friends have slept with more than 30 men--or have lost count. "Does this mean we are sexually empowered," she types, "or are we just sluts?"
At which point I replied aloud, "You mean you have DOUBTS?" [but I digress])
3) In a standard romance novel, the central relationship between hero and heroine (frankly, I find that terminology vaguely distasteful—it seems to imply that these characters are so stereotypical that they could easily be interchanged between books. Let's say, "main protagonists," shall we? Besides, that includes gay romances, and we are all for being inclusive, now, aren't we?) occupies 85-90% of the text, with all other plotlines being subordinated to the evolution of the relationship.
In ChickLit, the evolution of the romance is only 30-40% of the text, the rest being divided between the vicissitudes of the central character's work-life, and her sense of discovery of herself as a human being.
That said, both standard romance and ChickLit novels are courtship stories. They end (happily, always) when the central couple become mated—whether this indicates actual marriage, or merely the realization that we're going to be sexually monogamous for the next little while. And they never have sequels, because the story's over once mating is accomplished.
Now, "Women's Fiction"...this is usually code for "story about strong female relationships/quest for empowerment/mother-daughter issues/men would not be interested," and doesn't necessarily have a strong romantic plotline at all (in the most 'literary' kinds of Women's Fiction, men are generally viewed as alien creatures (at the very least), if not complete beasts. They're often rapists, abusers, manipulators, and generally a threat to whatever the central character is trying to achieve--and they _never_ understand the Sacred Bond of Sisterhood).
Mind, this is just my Very Humble Opinion [cough]—but you did ask. And it _is_ just an opinion, because I don't write in any of these genres myself. Though I guess I could be considered to be historical fiction, if it weren't for the time-travel, even though I do write about sex very well [she says modestly].