You can argue this both ways.
You can say that it is because it is a grassroots, spontaneous protest against what the left sees as the basic problems facing our society. Like the earliest parts of the Tea Party, OWS seems to be drawn from the more extreme end of the political spectrum. It is a movement that essentially sprang up out of nowhere because the people farthest to the left are dissatisfied with US government and society. In this way, it is like the Tea Party, which sprang up because those farthest on the right were unhappy.
I would argue, however, that it is not an answer to the Tea Party. The reason for this is that the Tea Party was very specific in its focus on government spending and taxation. The Tea Party had very clear goals. It wanted government to tax less and spend less. This allowed it to spread and become more popular (though its popularity is declining) with the general public. By contrast, OWS has no such clear goals. It is not set up to try to combat the Tea Party and its goals. Instead, it advocates some diffuse kind of general change.
So, in terms of how it came about, and from what part of the political spectrum, OWS is the liberal answer to the Tea Party. In terms of tactics and political efficacy, it does not seem to be something that the Democratic Party is likely to be able to harness and use to its advantage in the way the Republicans have used the Tea Party.
(Of course, the Tea Party has been around longer and has evolved to some degree. OWS could yet evolve and prove me wrong.)