user6273: You see this style often in animated videos, e.g. this one: 



The outer borders/lines of the elements sort of wiggle (for want of a better word) at a high frequency, giving the video more overall movement/activity. Of course for traditional animation that is drawn frame by frame, this is a byproduct of the illustrator drawing the shapes a bit differently every time. However, the video I linked above rather looks like most of it's elements were animated in After Effects (or similar software) rather than being hand-drawn frame by frame. 
I see this style quite often, I would like to know if this most likely an intentional effect (for example to give the impression of a hand-drawn animation) or the byproduct of a digital animation method. Also, is there an easy way to replicate this effect in After Effects without having to draw every frame (or manually transform the paths of my vector elements every frame)?

user1950: The style imitates hand-drawn cel animation, where each frame is drawn separately. Usually the lines will be slightly different in each drawing so you get what is called "boiling" or "line boil". 
This can be seen as a defect, but can also be used to give a stylistic look, much the same way as film scratches, lens flares, fogging etc. are added to animation that is created on a computer.
Turbulent displace can be used in After effects to simulate it, as discussed in this tutorial.

user3354: This seems to typically be called 'Squigglevision', it's even patented. There do seem do be ways to replicate this in After Effects.

6273: <p>You see this style often in animated videos, e.g. this one: </p>

<p><div class="youtube-embed"><div>
                <iframe width="640px" height="395px" src="https://www.youtube.com/embed/GVU_zANtroE?start=0"></iframe>
            </div></div></p>

<p>The outer borders/lines of the elements sort of wiggle (for want of a better word) at a high frequency, giving the video more overall movement/activity. Of course for traditional animation that is drawn frame by frame, this is a byproduct of the illustrator drawing the shapes a bit differently every time. However, the video I linked above rather looks like most of it's elements were animated in After Effects (or similar software) rather than being hand-drawn frame by frame. </p>

<p>I see this style quite often, I would like to know if this most likely an intentional effect (for example to give the impression of a hand-drawn animation) or the byproduct of a digital animation method. Also, is there an easy way to replicate this effect in After Effects without having to draw every frame (or manually transform the paths of my vector elements every frame)?</p>
 1950: <p>The style imitates hand-drawn cel animation, where each frame is drawn separately. Usually the lines will be slightly different in each drawing so you get what is called <a href="http://tvtropes.org/pmwiki/pmwiki.php/Main/LineBoil" rel="nofollow noreferrer">"boiling" or "line boil"</a>. </p>

<p>This can be seen as a defect, but can also be used to give a stylistic look, much the same way as film scratches, lens flares, fogging etc. are added to animation that is created on a computer.</p>

<p>Turbulent displace can be used in After effects to simulate it, as discussed in <a href="http://lesterbanks.com/2014/05/easily-build-animated-cartoon-line-effect-ae/" rel="nofollow noreferrer">this tutorial</a>.</p>
 3354: <p>This seems to typically be called <a href="https://en.wikipedia.org/wiki/Squigglevision" rel="nofollow noreferrer">'Squigglevision'</a>, it's even <a href="http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&amp;Sect2=HITOFF&amp;d=PALL&amp;p=1&amp;u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&amp;r=1&amp;f=G&amp;l=50&amp;s1=6252604.PN.&amp;OS=PN/6252604&amp;RS=PN/6252604" rel="nofollow noreferrer">patented</a>. There do seem do be ways to <a href="https://www.youtube.com/watch?v=Sh8l0q7XySk" rel="nofollow noreferrer">replicate this in After Effects</a>.</p>
