I second the excellent answer above by jk180.  The poem may be cited as a depiction of individuality, but doing so would be erroneous.  The paths the speaker originally comes across are basically the same.  He does not travel the road less-traveled.  The roads are similar, and worn about the same.

In the fourth stanza, the speaker imagines himself using the fork in the road incident to tell a story and pretend one path was less-traveled than the other.  He will play the role of a wise old man and tell others that he chose the unpopular path and that has made all the difference.  But he will be telling a white lie, or making up a fish story, so to speak.

A full summary of Robert Frost's poem needs to, I believe, cover the content of all of the stanzas and refrain from making interpretive statements (as such statements fall under the topic of "theme" more than "summary"). To add to the first poster's summary in the first three sentences, then, I would add the following:

The first three stanzas make consistent use of the past tense. These stanzas are rich in imagery that present the two paths as different and yet the same. The fourth stanza contains a shift in time from the past to future. The speaker now reflects on how, some time in the future, he or she will look back and assign great significance ("all the difference") to the choice of one path over the other.

See the "meaning" section in the link below for another summary of the poem.

Robert Frost's The Road Not Taken is a poem about a traveler walking along a path. In four stanzas, the author tells this story: The traveler comes across a fork in the road, where there are two choices of where he could walk. He looks at both of the paths and deliberates, and then chooses the road that is less taken, thereby choosing a different path than most people. This poem is often seen as a statement of individuality. Walking down the "road not taken" as often will take someone to a different place than most people. If you make different choices in life, you won't end up like everyone else. The poem also makes the subtle point that you never really know where you'll end up until you take the risk and choose the path. 

"The Road Not Taken" is one of Robert Frost's most famous poems. It is comprised of four stanzas, each with five lines and each adhering to the same rhyme scheme: ABAAB. The poem has been very much thought over by critics, who have questioned the meaning of the road, the idea of the journey, and what is represented. However, Frost himself suggested that the poem was simply about a literal occurrence that took place when he was out walking with his friend, the Welsh poet Edward Thomas, who was always, according to Frost, indecisive in terms of choosing a route to take.

The speaker in the poem describes coming to a place in a "yellow wood" where one road turned into two forks. The traveler is sorry that he can't take both routes, so he stands there for a long time, looking down the paths to try and discern which would be the best one to take. Having looked a long while down one path, he eventually takes the other, "just as fair," because it appears to be ever so slightly less well-worn than the other—but the speaker makes clear that the difference is minimal.

The speaker says that he told himself at the time that he had left the other route "for another day," but that in his heart he suspected he would not have a chance to come back and try it again. He then says he may one day be telling this story to others "ages and ages hence" and that determining that having taken the road "less traveled by" has "made all the difference."

A traveler comes to a fork in the road.  He looks at one path and follows it with his eye as far as he can until it bends into the forest.  Then he looks at the other path, noting that it is grassier, a fact which may make it a little more appealing, though it looks like about the same number of people have taken each path.  He comments that both of the paths are covered in fresh leaves, and he decides to take the second path (the grassier one), and he wonders if he'll ever be able to come back and take the first path (but he knows that it is really unlikely because of the way choices work).  He considers the future, when he will, at some point, describe this choice: he plans to say that, when faced with two paths (or two options, symbolically), he took the path that fewer people have traveled and that this choice has made a big difference in how his life turned out.  (In other words, he plans to lie.)