In the meantime, I recently made a template called "Travel Light...". This template is fantastic as it lets me explore with creating what could be considered a very small capsule wardrobe (twelve clothing items, three pairs of shoes, and two bags). It's interesting to see the diverse number of outfits that can be derived from these twelve items, those that are both casual and dressy.
One of my more recent uses of this template was "Travel Light... Prague", pictured below.
This is not simply what to bring for a long weekend (I should be so lucky to have a "long weekend" in Europe...). A quick count showed twenty-one different outfits. And this initial count does not reflect the versatility of having both a trenchcoat and a blazer. Really these allow you to get two very different looks out of one outfit. For example a more dressy look...
As you can see, I swapped out accessories to accentuate the difference, however, even keeping both the day bag and the sandals constant, two very different looks are created.
So as I promised... the many reasons I find Polyvore an excellent tool. When I first joined I focused on finding members who created sets that reflected what I gravitated towards style-wise. After liking a number of them--and following their creators--I was able to look at all of my "likes" together and see trends (mostly neutrals, lots of stripes, clean lines and tailoring but often ever-so-slightly laid-back, etc.). These helped me to define my personal style more clearly to myself.
Further, when thinking of splurging on an item, it's helpful to be able to try it out in various ways with clothes that are similar to what you have in your closet. This way, you are able to ascertain how well the piece integrates.
Finally (although these are certainly not the only reasons I love Polyvore), and perhaps most simply, it offers a great creative outlet. It doesn't tell you what to do and how to do it, but rather offers you the tools needed to create. As well as a following of users who may offer input regarding what you're doing.