What's in a trend?

What is it that makes something trendy?

Is it that its innovative?
These menswear shoes by Martinez Velero (Sachi) are currently one of the key trends referenced in a number of shoe trendwatches, but they are hardly "new." I like!


Is it that its different than what has been seen recently?
These pumps, (BCBGirls Stela) in an oaky-colored brown, are highlighted as "what's in for fall" because of their color. Brown is always in, isn't it? I probably wouldn't buy these, personally, because I think that they look old, but they aren't bad.
Is it that this particular style or color or feature is especially seasonal?
Steve Madden recently introduced these sandals for the fall. My feet get cold just looking at them! I do like the gladiator look, though.