On December 13, 1845, the Broadway Journal printed a review of Poems, a collection of poetry by Frances Sargent Osgood. Poe praises her work for its "happy refinement" and noted that its author "gives a charm inexpressible to everything which flows from her pen." Poe's opinion of Osgood, however, may be partially tainted by their personal relationship. Earlier that year, the two had engaged in a heavy (and public) literary flirtation while Poe's wife Virginia was sick. They exchanged poems addressed to one another in Poe's own magazine, the Broadway Journal.
Interpretations of the relationship between Poe and Fanny Osgood are wide-ranging. Both were married at the time, though rumors suggest that Osgood was "estranged" from her husband, the artist Samuel Stillman Osgood. One person, noted for being a bit of a trouble maker, suggested that Osgood's third daughter, Fanny Fay, was actually the bastard child from the affair with Poe. Little Fanny Fay did not survive long and, though no evidence supports Elizabeth Ellet's claim, some modern scholars suggest that Poe's poem "Ulalume" is about his lost child.
Rufus Griswold almost certainly developed a crush on Osgood too. It seems to me that Osgood was a bit too flirtatious for her own good and some weak-willed men, like Griswold, read too much into it. Nevertheless, rivalry for the attention of Osgood may have led Griswold to build up further spite against Poe.
Ultimately, there is very little about Osgood's poetry that is memorable. A stereotypical woman poet of her era, much of her work has a damsel in distress vibe to it. Breathy, overloaded with dashes and exclamation points, most of her poems use some version of the word "sigh" at least once. One is about a faithful dog that does not leave his master's side, even as he is dying. Not very profound stuff.
The reality seems to be that the poetry exchanged by Osgood and Poe was platonic, not hot and heavy as some suggest (apparently without reading the interchanges). One, for example, was published in the same issue as Poe's review of Osgood's poetry. It is addressed to Poe and poetically notes how she takes a risk in writing her poetry, launches it like a ship, and tries to find a sympathetic "friend." Poe, the "you" of the poem, should be the pilot of the ship, she says. So, Poe is steering her poetry (like the editor he was), as she tries to find a friend. Not much scandal there, really.
Nevertheless, some even go so far as to say that the strange romance (which it was not) led to the creation of one of the greatest American masterpieces ever written. If you'll excuse me, there is no evidence whatsoever to support this conclusion. None. And the base generalizations in the article, the assumptions one must make for this theory to be plausible, have no basis either (Fanny Osgood as one of the most written about poets? Give me an example. Then explain to me how the infamously-reclusive, anti-women-writers Hawthorne even knew Osgood, let alone was interested in her enough to turn her into Hester Prynne).